21236596538 has 4 divisors (see below), whose sum is σ = 31854894810. Its totient is φ = 10618298268.

The previous prime is 21236596523. The next prime is 21236596543. The reversal of 21236596538 is 83569563212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 10651684849 + 10584911689 = 103207^2 + 102883^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5309149133 + ... + 5309149136.

Almost surely, 2^21236596538 is an apocalyptic number.

21236596538 is a deficient number, since it is larger than the sum of its proper divisors (10618298272).

21236596538 is a wasteful number, since it uses less digits than its factorization.

21236596538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10618298271.

The product of its digits is 2332800, while the sum is 50.

The spelling of 21236596538 in words is "twenty-one billion, two hundred thirty-six million, five hundred ninety-six thousand, five hundred thirty-eight".