21547778604 has 24 divisors (see below), whose sum is σ = 54848891328. Its totient is φ = 6529629840.

The previous prime is 21547778591. The next prime is 21547778617. The reversal of 21547778604 is 40687774512.

It is an interprime number because it is at equal distance from previous prime (21547778591) and next prime (21547778617).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81620242 + ... + 81620505.

It is an arithmetic number, because the mean of its divisors is an integer number (2285370472).

Almost surely, 2^21547778604 is an apocalyptic number.

It is an amenable number.

21547778604 is an abundant number, since it is smaller than the sum of its proper divisors (33301112724).

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

21547778604 is a wasteful number, since it uses less digits than its factorization.

21547778604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163240765 (or 163240763 counting only the distinct ones).

The product of its (nonzero) digits is 2634240, while the sum is 51.

The spelling of 21547778604 in words is "twenty-one billion, five hundred forty-seven million, seven hundred seventy-eight thousand, six hundred four".