21210552520 has 32 divisors (see below), whose sum is σ = 50531023800. Its totient is φ = 7985148928.

The previous prime is 21210552499. The next prime is 21210552533. The reversal of 21210552520 is 2525501212.

It can be written as a sum of positive squares in 4 ways, for example, as 18307713636 + 2902838884 = 135306^2 + 53878^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15595315 + ... + 15596674.

Almost surely, 2^21210552520 is an apocalyptic number.

21210552520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210552520 is an abundant number, since it is smaller than the sum of its proper divisors (29320471280).

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

21210552520 is a wasteful number, since it uses less digits than its factorization.

21210552520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31192017 (or 31192013 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 25.

The spelling of 21210552520 in words is "twenty-one billion, two hundred ten million, five hundred fifty-two thousand, five hundred twenty".