21806588392 has 16 divisors (see below), whose sum is σ = 41658813540. Its totient is φ = 10697571456.

The previous prime is 21806588311. The next prime is 21806588393. The reversal of 21806588392 is 29388560812.

It can be written as a sum of positive squares in 2 ways, for example, as 21789892996 + 16695396 = 147614^2 + 4086^2 .

It is not an unprimeable number, because it can be changed into a prime (21806588393) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25714893 + ... + 25715740.

Almost surely, 2^21806588392 is an apocalyptic number.

It is an amenable number.

21806588392 is a deficient number, since it is larger than the sum of its proper divisors (19852225148).

21806588392 is a wasteful number, since it uses less digits than its factorization.

21806588392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51430692 (or 51430688 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 52.

The spelling of 21806588392 in words is "twenty-one billion, eight hundred six million, five hundred eighty-eight thousand, three hundred ninety-two".