1021620520 has 16 divisors (see below), whose sum is σ = 2298646260. Its totient is φ = 408648192.

The previous prime is 1021620511. The next prime is 1021620521. The reversal of 1021620520 is 250261201.

It can be written as a sum of positive squares in 2 ways, for example, as 1021569444 + 51076 = 31962^2 + 226^2 .

It is not an unprimeable number, because it can be changed into a prime (1021620521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12770217 + ... + 12770296.

Almost surely, 2^1021620520 is an apocalyptic number.

1021620520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1021620520 is an abundant number, since it is smaller than the sum of its proper divisors (1277025740).

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

1021620520 is a wasteful number, since it uses less digits than its factorization.

1021620520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25540524 (or 25540520 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1021620520 is about 31962.7990013390. The cubic root of 1021620520 is about 1007.1555164600.

Adding to 1021620520 its reverse (250261201), we get a palindrome (1271881721).

The spelling of 1021620520 in words is "one billion, twenty-one million, six hundred twenty thousand, five hundred twenty".