21138084678 has 16 divisors (see below), whose sum is σ = 42280451136. Its totient is φ = 7045314600.

The previous prime is 21138084661. The next prime is 21138084683. The reversal of 21138084678 is 87648083112.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112348 + ... + 234303.

It is an arithmetic number, because the mean of its divisors is an integer number (2642528196).

Almost surely, 2^21138084678 is an apocalyptic number.

21138084678 is an abundant number, since it is smaller than the sum of its proper divisors (21142366458).

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

21138084678 is a wasteful number, since it uses less digits than its factorization.

21138084678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356819.

The product of its (nonzero) digits is 516096, while the sum is 48.

The spelling of 21138084678 in words is "twenty-one billion, one hundred thirty-eight million, eighty-four thousand, six hundred seventy-eight".