21923687838 has 32 divisors (see below), whose sum is σ = 47227775616. Its totient is φ = 6744675168.

The previous prime is 21923687831. The next prime is 21923687861. The reversal of 21923687838 is 83878632912.

It is a super-2 number, since 2×21923687838² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21923687831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 570045 + ... + 607287.

It is an arithmetic number, because the mean of its divisors is an integer number (1475867988).

Almost surely, 2^21923687838 is an apocalyptic number.

21923687838 is an abundant number, since it is smaller than the sum of its proper divisors (25304087778).

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

21923687838 is a wasteful number, since it uses less digits than its factorization.

21923687838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44808.

The product of its digits is 6967296, while the sum is 57.

The spelling of 21923687838 in words is "twenty-one billion, nine hundred twenty-three million, six hundred eighty-seven thousand, eight hundred thirty-eight".