20138659968 has 128 divisors (see below), whose sum is σ = 64353024000. Its totient is φ = 5451052032.

The previous prime is 20138659951. The next prime is 20138660027. The reversal of 20138659968 is 86995683102.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×20138659968² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146088 + ... + 248231.

It is an arithmetic number, because the mean of its divisors is an integer number (502758000).

Almost surely, 2^20138659968 is an apocalyptic number.

20138659968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20138659968 is an abundant number, since it is smaller than the sum of its proper divisors (44214364032).

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

20138659968 is a wasteful number, since it uses less digits than its factorization.

20138659968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394362 (or 394350 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 57.

The spelling of 20138659968 in words is "twenty billion, one hundred thirty-eight million, six hundred fifty-nine thousand, nine hundred sixty-eight".