21527905881 has 4 divisors (see below), whose sum is σ = 28703874512. Its totient is φ = 14351937252.

The previous prime is 21527905873. The next prime is 21527905909. The reversal of 21527905881 is 18850972512.

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 21527905881 - 2³ = 21527905873 is a prime.

It is a super-2 number, since 2×21527905881² (a number of 21 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 21527905881.

It is not an unprimeable number, because it can be changed into a prime (21527905871) 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, 3587984311 + ... + 3587984316.

It is an arithmetic number, because the mean of its divisors is an integer number (7175968628).

Almost surely, 2^21527905881 is an apocalyptic number.

It is an amenable number.

21527905881 is a deficient number, since it is larger than the sum of its proper divisors (7175968631).

21527905881 is an equidigital number, since it uses as much as digits as its factorization.

21527905881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7175968630.

The product of its (nonzero) digits is 403200, while the sum is 48.

The spelling of 21527905881 in words is "twenty-one billion, five hundred twenty-seven million, nine hundred five thousand, eight hundred eighty-one".