21163025536 has 64 divisors (see below), whose sum is σ = 42439017600. Its totient is φ = 10511907840.

The previous prime is 21163025509. The next prime is 21163025539. The reversal of 21163025536 is 63552036112.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (21163025539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24809686 + ... + 24810538.

It is an arithmetic number, because the mean of its divisors is an integer number (663109650).

Almost surely, 2^21163025536 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 21163025536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21219508800).

21163025536 is an abundant number, since it is smaller than the sum of its proper divisors (21275992064).

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

21163025536 is an equidigital number, since it uses as much as digits as its factorization.

21163025536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1917 (or 1905 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 34.

The spelling of 21163025536 in words is "twenty-one billion, one hundred sixty-three million, twenty-five thousand, five hundred thirty-six".