21885018891 has 8 divisors (see below), whose sum is σ = 29615548224. Its totient is φ = 14372251080.

The previous prime is 21885018803. The next prime is 21885018893. The reversal of 21885018891 is 19881058812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21885018891 - 2⁷ = 21885018763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21885018893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54440145 + ... + 54440546.

It is an arithmetic number, because the mean of its divisors is an integer number (3701943528).

Almost surely, 2^21885018891 is an apocalyptic number.

21885018891 is a deficient number, since it is larger than the sum of its proper divisors (7730529333).

21885018891 is a wasteful number, since it uses less digits than its factorization.

21885018891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108880761.

The product of its (nonzero) digits is 368640, while the sum is 51.

The spelling of 21885018891 in words is "twenty-one billion, eight hundred eighty-five million, eighteen thousand, eight hundred ninety-one".