21295478780 has 24 divisors (see below), whose sum is σ = 44725222752. Its totient is φ = 8517292992.

The previous prime is 21295478747. The next prime is 21295478803. The reversal of 21295478780 is 8787459212.

It is a super-3 number, since 3×21295478780³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158129 + ... + 259991.

It is an arithmetic number, because the mean of its divisors is an integer number (1863550948).

Almost surely, 2^21295478780 is an apocalyptic number.

21295478780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21295478780 is an abundant number, since it is smaller than the sum of its proper divisors (23429743972).

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

21295478780 is a wasteful number, since it uses less digits than its factorization.

21295478780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112325 (or 112323 counting only the distinct ones).

The product of its (nonzero) digits is 2257920, while the sum is 53.

The spelling of 21295478780 in words is "twenty-one billion, two hundred ninety-five million, four hundred seventy-eight thousand, seven hundred eighty".