21677661816 has 32 divisors (see below), whose sum is σ = 54217386240. Its totient is φ = 7222789728.

The previous prime is 21677661757. The next prime is 21677661821. The reversal of 21677661816 is 61816677612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136096 + ... + 248751.

It is an arithmetic number, because the mean of its divisors is an integer number (1694293320).

Almost surely, 2^21677661816 is an apocalyptic number.

It is an amenable number.

21677661816 is an abundant number, since it is smaller than the sum of its proper divisors (32539724424).

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

21677661816 is a wasteful number, since it uses less digits than its factorization.

21677661816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387203 (or 387199 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 51.

The spelling of 21677661816 in words is "twenty-one billion, six hundred seventy-seven million, six hundred sixty-one thousand, eight hundred sixteen".