21504131493 has 32 divisors (see below), whose sum is σ = 31219827072. Its totient is φ = 13087008000.

The previous prime is 21504131489. The next prime is 21504131507. The reversal of 21504131493 is 39413140512.

It is not a de Polignac number, because 21504131493 - 2² = 21504131489 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504131413) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4019046 + ... + 4024392.

It is an arithmetic number, because the mean of its divisors is an integer number (975619596).

Almost surely, 2^21504131493 is an apocalyptic number.

It is an amenable number.

21504131493 is a deficient number, since it is larger than the sum of its proper divisors (9715695579).

21504131493 is a wasteful number, since it uses less digits than its factorization.

21504131493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6485.

The product of its (nonzero) digits is 12960, while the sum is 33.

The spelling of 21504131493 in words is "twenty-one billion, five hundred four million, one hundred thirty-one thousand, four hundred ninety-three".