21603217512621 has 4 divisors (see below), whose sum is σ = 28804290016832. Its totient is φ = 14402145008412.

The previous prime is 21603217512601. The next prime is 21603217512671. The reversal of 21603217512621 is 12621571230612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21603217512621 - 2⁶ = 21603217512557 is a prime.

It is a super-2 number, since 2×21603217512621² (a number of 27 digits) contains 22 as substring.

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 21603217512621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21603217512601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3600536252101 + ... + 3600536252106.

It is an arithmetic number, because the mean of its divisors is an integer number (7201072504208).

Almost surely, 2^{21603217512621} is an apocalyptic number.

It is an amenable number.

21603217512621 is a deficient number, since it is larger than the sum of its proper divisors (7201072504211).

21603217512621 is an equidigital number, since it uses as much as digits as its factorization.

21603217512621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7201072504210.

The product of its (nonzero) digits is 60480, while the sum is 39.

The spelling of 21603217512621 in words is "twenty-one trillion, six hundred three billion, two hundred seventeen million, five hundred twelve thousand, six hundred twenty-one".