21638151938 has 32 divisors (see below), whose sum is σ = 37011475200. Its totient is φ = 9461179728.

The previous prime is 21638151911. The next prime is 21638151943. The reversal of 21638151938 is 83915183612.

It is a junction number, because it is equal to n+sod(n) for n = 21638151892 and 21638151901.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46106 + ... + 213077.

It is an arithmetic number, because the mean of its divisors is an integer number (1156608600).

Almost surely, 2^21638151938 is an apocalyptic number.

21638151938 is a deficient number, since it is larger than the sum of its proper divisors (15373323262).

21638151938 is a wasteful number, since it uses less digits than its factorization.

21638151938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259243 (or 259217 counting only the distinct ones).

The product of its digits is 311040, while the sum is 47.

The spelling of 21638151938 in words is "twenty-one billion, six hundred thirty-eight million, one hundred fifty-one thousand, nine hundred thirty-eight".