21169512738 has 48 divisors (see below), whose sum is σ = 50197039776. Its totient is φ = 6394489920.

The previous prime is 21169512737. The next prime is 21169512743. The reversal of 21169512738 is 83721596112.

21169512738 is a `hidden beast` number, since 2 + 1 + 1 + 69 + 512 + 73 + 8 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21169512693 and 21169512702.

It is not an unprimeable number, because it can be changed into a prime (21169512733) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 108820 + ... + 232767.

It is an arithmetic number, because the mean of its divisors is an integer number (1045771662).

Almost surely, 2^21169512738 is an apocalyptic number.

21169512738 is an abundant number, since it is smaller than the sum of its proper divisors (29027527038).

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

21169512738 is a wasteful number, since it uses less digits than its factorization.

21169512738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341919 (or 341916 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The spelling of 21169512738 in words is "twenty-one billion, one hundred sixty-nine million, five hundred twelve thousand, seven hundred thirty-eight".