21088125091 has 16 divisors (see below), whose sum is σ = 23454362880. Its totient is φ = 18798389280.

The previous prime is 21088125077. The next prime is 21088125103. The reversal of 21088125091 is 19052188012.

It is not a de Polignac number, because 21088125091 - 2²⁵ = 21054570659 is a prime.

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 21088125091.

It is not an unprimeable number, because it can be changed into a prime (21088125011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 216730 + ... + 298576.

It is an arithmetic number, because the mean of its divisors is an integer number (1465897680).

Almost surely, 2^21088125091 is an apocalyptic number.

21088125091 is a deficient number, since it is larger than the sum of its proper divisors (2366237789).

21088125091 is a wasteful number, since it uses less digits than its factorization.

21088125091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82314.

The product of its (nonzero) digits is 11520, while the sum is 37.

The spelling of 21088125091 in words is "twenty-one billion, eighty-eight million, one hundred twenty-five thousand, ninety-one".