21627530657 has 4 divisors (see below), whose sum is σ = 21633257520. Its totient is φ = 21621803796.

The previous prime is 21627530641. The next prime is 21627530723. The reversal of 21627530657 is 75603572612.

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 a cyclic number.

It is not a de Polignac number, because 21627530657 - 2⁴ = 21627530641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21627538657) 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, 2857763 + ... + 2865320.

It is an arithmetic number, because the mean of its divisors is an integer number (5408314380).

Almost surely, 2^21627530657 is an apocalyptic number.

It is an amenable number.

21627530657 is a deficient number, since it is larger than the sum of its proper divisors (5726863).

21627530657 is an equidigital number, since it uses as much as digits as its factorization.

21627530657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5726862.

The product of its (nonzero) digits is 529200, while the sum is 44.

The spelling of 21627530657 in words is "twenty-one billion, six hundred twenty-seven million, five hundred thirty thousand, six hundred fifty-seven".