21439178401540 has 24 divisors (see below), whose sum is σ = 45056880596952. Its totient is φ = 8569079750400.

The previous prime is 21439178401489. The next prime is 21439178401561. The reversal of 21439178401540 is 4510487193412.

It can be written as a sum of positive squares in 4 ways, for example, as 204334737156 + 21234843664384 = 452034^2 + 4608128^2 .

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, 411948969 + ... + 412001008.

It is an arithmetic number, because the mean of its divisors is an integer number (1877370024873).

Almost surely, 2^{21439178401540} is an apocalyptic number.

21439178401540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21439178401540 is an abundant number, since it is smaller than the sum of its proper divisors (23617702195412).

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

21439178401540 is a wasteful number, since it uses less digits than its factorization.

21439178401540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823951287 (or 823951285 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 49.

The spelling of 21439178401540 in words is "twenty-one trillion, four hundred thirty-nine billion, one hundred seventy-eight million, four hundred one thousand, five hundred forty".