1021541220 has 360 divisors, whose sum is σ = 3952312056. Its totient is φ = 219469824.

The previous prime is 1021541207. The next prime is 1021541231. The reversal of 1021541220 is 221451201.

1021541220 is a `hidden beast` number, since 102 + 1 + 541 + 2 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 260112384 + 761428836 = 16128^2 + 27594^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1021541193 and 1021541202.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 1349082 + ... + 1349838.

Almost surely, 2^1021541220 is an apocalyptic number.

1021541220 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 1021541220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1976156028).

1021541220 is an abundant number, since it is smaller than the sum of its proper divisors (2930770836).

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

1021541220 is a wasteful number, since it uses less digits than its factorization.

1021541220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 809 (or 791 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 1021541220 is about 31961.5584726402. The cubic root of 1021541220 is about 1007.1294567188.

Adding to 1021541220 its reverse (221451201), we get a palindrome (1242992421).

The spelling of 1021541220 in words is "one billion, twenty-one million, five hundred forty-one thousand, two hundred twenty".