21523550520 has 64 divisors (see below), whose sum is σ = 64671304320. Its totient is φ = 5730666624.

The previous prime is 21523550507. The next prime is 21523550533. The reversal of 21523550520 is 2505532512.

It is an interprime number because it is at equal distance from previous prime (21523550507) and next prime (21523550533).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62314 + ... + 216633.

It is an arithmetic number, because the mean of its divisors is an integer number (1010489130).

Almost surely, 2^21523550520 is an apocalyptic number.

21523550520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21523550520 is an abundant number, since it is smaller than the sum of its proper divisors (43147753800).

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

21523550520 is a wasteful number, since it uses less digits than its factorization.

21523550520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279604 (or 279600 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 30.

The spelling of 21523550520 in words is "twenty-one billion, five hundred twenty-three million, five hundred fifty thousand, five hundred twenty".