21507526742621 has 16 divisors (see below), whose sum is σ = 21671866022400. Its totient is φ = 21343753912320.

The previous prime is 21507526742617. The next prime is 21507526742659. The reversal of 21507526742621 is 12624762570512.

It is a cyclic number.

It is not a de Polignac number, because 21507526742621 - 2² = 21507526742617 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21507526742621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21507526742021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 435253406 + ... + 435302816.

It is an arithmetic number, because the mean of its divisors is an integer number (1354491626400).

Almost surely, 2^{21507526742621} is an apocalyptic number.

It is an amenable number.

21507526742621 is a deficient number, since it is larger than the sum of its proper divisors (164339279779).

21507526742621 is a wasteful number, since it uses less digits than its factorization.

21507526742621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55076.

The product of its (nonzero) digits is 2822400, while the sum is 50.

The spelling of 21507526742621 in words is "twenty-one trillion, five hundred seven billion, five hundred twenty-six million, seven hundred forty-two thousand, six hundred twenty-one".