21603125916 has 72 divisors (see below), whose sum is σ = 56131224240. Its totient is φ = 7000494336.

The previous prime is 21603125881. The next prime is 21603125923. The reversal of 21603125916 is 61952130612.

21603125916 is a `hidden beast` number, since 2 + 1 + 60 + 3 + 1 + 2 + 591 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1734720 + ... + 1747128.

Almost surely, 2^21603125916 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 21603125916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28065612120).

21603125916 is an abundant number, since it is smaller than the sum of its proper divisors (34528098324).

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

21603125916 is a wasteful number, since it uses less digits than its factorization.

21603125916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13763 (or 13758 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The spelling of 21603125916 in words is "twenty-one billion, six hundred three million, one hundred twenty-five thousand, nine hundred sixteen".