21627530681 has 4 divisors (see below), whose sum is σ = 21628788864. Its totient is φ = 21626272500.

The previous prime is 21627530641. The next prime is 21627530723. The reversal of 21627530681 is 18603572612.

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 21627530681 - 2³⁴ = 4447661497 is a prime.

It is a super-2 number, since 2×21627530681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21627530641) 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, 602945 + ... + 637806.

It is an arithmetic number, because the mean of its divisors is an integer number (5407197216).

Almost surely, 2^21627530681 is an apocalyptic number.

It is an amenable number.

21627530681 is a deficient number, since it is larger than the sum of its proper divisors (1258183).

21627530681 is a wasteful number, since it uses less digits than its factorization.

21627530681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1258182.

The product of its (nonzero) digits is 120960, while the sum is 41.

The spelling of 21627530681 in words is "twenty-one billion, six hundred twenty-seven million, five hundred thirty thousand, six hundred eighty-one".