20891627838 has 16 divisors (see below), whose sum is σ = 46425839760. Its totient is φ = 6963875928.

The previous prime is 20891627831. The next prime is 20891627863. The reversal of 20891627838 is 83872619802.

It is a happy number.

20891627838 is a `hidden beast` number, since 2 + 0 + 8 + 9 + 1 + 627 + 8 + 3 + 8 = 666.

It is a super-3 number, since 3×20891627838³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (54), and also a Moran number because the ratio is a prime number: 386881997 = 20891627838 / (2 + 0 + 8 + 9 + 1 + 6 + 2 + 7 + 8 + 3 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891627831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 193440945 + ... + 193441052.

It is an arithmetic number, because the mean of its divisors is an integer number (2901614985).

Almost surely, 2^20891627838 is an apocalyptic number.

20891627838 is an abundant number, since it is smaller than the sum of its proper divisors (25534211922).

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

20891627838 is a wasteful number, since it uses less digits than its factorization.

20891627838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386882008 (or 386882002 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 20891627838 in words is "twenty billion, eight hundred ninety-one million, six hundred twenty-seven thousand, eight hundred thirty-eight".