21986091625 has 8 divisors (see below), whose sum is σ = 27438642504. Its totient is φ = 17588873200.

The previous prime is 21986091599. The next prime is 21986091629. The reversal of 21986091625 is 52619068912.

It can be written as a sum of positive squares in 4 ways, for example, as 98664489 + 21887427136 = 9933^2 + 147944^2 .

It is not a de Polignac number, because 21986091625 - 2³¹ = 19838607977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21986091629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87944242 + ... + 87944491.

It is an arithmetic number, because the mean of its divisors is an integer number (3429830313).

Almost surely, 2^21986091625 is an apocalyptic number.

21986091625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21986091625 is a deficient number, since it is larger than the sum of its proper divisors (5452550879).

21986091625 is an equidigital number, since it uses as much as digits as its factorization.

21986091625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175888748 (or 175888738 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 49.

The spelling of 21986091625 in words is "twenty-one billion, nine hundred eighty-six million, ninety-one thousand, six hundred twenty-five".