21723865185640 has 64 divisors (see below), whose sum is σ = 51452076744000. Its totient is φ = 8232070809600.

The previous prime is 21723865185629. The next prime is 21723865185667. The reversal of 21723865185640 is 4658156832712.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57220440 + ... + 57598840.

It is an arithmetic number, because the mean of its divisors is an integer number (803938699125).

Almost surely, 2^{21723865185640} is an apocalyptic number.

21723865185640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21723865185640 is an abundant number, since it is smaller than the sum of its proper divisors (29728211558360).

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

21723865185640 is a wasteful number, since it uses less digits than its factorization.

21723865185640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453970 (or 453966 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 58.

The spelling of 21723865185640 in words is "twenty-one trillion, seven hundred twenty-three billion, eight hundred sixty-five million, one hundred eighty-five thousand, six hundred forty".