21877948638 has 128 divisors (see below), whose sum is σ = 61900876800. Its totient is φ = 5571006336.

The previous prime is 21877948597. The next prime is 21877948709. The reversal of 21877948638 is 83684977812.

21877948638 is a `hidden beast` number, since 2 + 1 + 87 + 79 + 486 + 3 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 65745 + ... + 219267.

It is an arithmetic number, because the mean of its divisors is an integer number (483600600).

Almost surely, 2^21877948638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21877948638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30950438400).

21877948638 is an abundant number, since it is smaller than the sum of its proper divisors (40022928162).

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

21877948638 is a wasteful number, since it uses less digits than its factorization.

21877948638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153583 (or 153577 counting only the distinct ones).

The product of its digits is 32514048, while the sum is 63.

The spelling of 21877948638 in words is "twenty-one billion, eight hundred seventy-seven million, nine hundred forty-eight thousand, six hundred thirty-eight".