1021020520 has 64 divisors (see below), whose sum is σ = 2478425040. Its totient is φ = 376320000.

The previous prime is 1021020491. The next prime is 1021020529. The reversal of 1021020520 is 250201201.

It can be written as a sum of positive squares in 8 ways, for example, as 451052644 + 569967876 = 21238^2 + 23874^2 .

It is a super-2 number, since 2×1021020520² = 2084965804522140800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 1021020520.

It is not an unprimeable number, because it can be changed into a prime (1021020529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 363120 + ... + 365920.

Almost surely, 2^1021020520 is an apocalyptic number.

1021020520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1021020520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1239212520).

1021020520 is an abundant number, since it is smaller than the sum of its proper divisors (1457404520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1021020520 is a wasteful number, since it uses less digits than its factorization.

1021020520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3526 (or 3522 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 1021020520 is about 31953.4117114276. The cubic root of 1021020520 is about 1006.9583096245.

Adding to 1021020520 its reverse (250201201), we get a palindrome (1271221721).

It can be divided in two parts, 10210205 and 20, that multiplied together give a square (204204100 = 14290²).

The spelling of 1021020520 in words is "one billion, twenty-one million, twenty thousand, five hundred twenty".