21031766528 has 80 divisors (see below), whose sum is σ = 42487727040. Its totient is φ = 10400096256.

The previous prime is 21031766519. The next prime is 21031766533. The reversal of 21031766528 is 82566713012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30792875 + ... + 30793557.

It is an arithmetic number, because the mean of its divisors is an integer number (531096588).

Almost surely, 2^21031766528 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031766528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21243863520).

21031766528 is an abundant number, since it is smaller than the sum of its proper divisors (21455960512).

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

21031766528 is an equidigital number, since it uses as much as digits as its factorization.

21031766528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1277 (or 1261 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 21031766528 in words is "twenty-one billion, thirty-one million, seven hundred sixty-six thousand, five hundred twenty-eight".