91781825 has 6 divisors (see below), whose sum is σ = 113809494. Its totient is φ = 73425440.

The previous prime is 91781819. The next prime is 91781857. The reversal of 91781825 is 52818719.

It can be written as a sum of positive squares in 3 ways, for example, as 693889 + 91087936 = 833^2 + 9544^2 .

It is not a de Polignac number, because 91781825 - 2¹² = 91777729 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1835612 + ... + 1835661.

It is an arithmetic number, because the mean of its divisors is an integer number (18968249).

Almost surely, 2^91781825 is an apocalyptic number.

It is an amenable number.

91781825 is a deficient number, since it is larger than the sum of its proper divisors (22027669).

91781825 is a wasteful number, since it uses less digits than its factorization.

91781825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3671283 (or 3671278 counting only the distinct ones).

The product of its digits is 40320, while the sum is 41.

The square root of 91781825 is about 9580.2831377783. The cubic root of 91781825 is about 451.0786060368.

The spelling of 91781825 in words is "ninety-one million, seven hundred eighty-one thousand, eight hundred twenty-five".