91721258425 has 12 divisors (see below), whose sum is σ = 113739593836. Its totient is φ = 73373630400.

The previous prime is 91721258411. The next prime is 91721258507. The reversal of 91721258425 is 52485212719.

It can be written as a sum of positive squares in 6 ways, for example, as 36696766096 + 55024492329 = 191564^2 + 234573^2 .

It is not a de Polignac number, because 91721258425 - 2¹⁹ = 91720734137 is a prime.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 568927 + ... + 712123.

Almost surely, 2^91721258425 is an apocalyptic number.

It is an amenable number.

91721258425 is a deficient number, since it is larger than the sum of its proper divisors (22018335411).

91721258425 is a wasteful number, since it uses less digits than its factorization.

91721258425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168828 (or 168823 counting only the distinct ones).

The product of its digits is 403200, while the sum is 46.

The spelling of 91721258425 in words is "ninety-one billion, seven hundred twenty-one million, two hundred fifty-eight thousand, four hundred twenty-five".