91639457 has 24 divisors (see below), whose sum is σ = 115448256. Its totient is φ = 72098208.

The previous prime is 91639433. The next prime is 91639459. The reversal of 91639457 is 75493619.

It is not a de Polignac number, because 91639457 - 2¹² = 91635361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91639459) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 167258 + ... + 167804.

It is an arithmetic number, because the mean of its divisors is an integer number (4810344).

Almost surely, 2^91639457 is an apocalyptic number.

It is an amenable number.

91639457 is a deficient number, since it is larger than the sum of its proper divisors (23808799).

91639457 is a wasteful number, since it uses less digits than its factorization.

91639457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837 (or 830 counting only the distinct ones).

The product of its digits is 204120, while the sum is 44.

The square root of 91639457 is about 9572.8499936017. The cubic root of 91639457 is about 450.8452541275.

The spelling of 91639457 in words is "ninety-one million, six hundred thirty-nine thousand, four hundred fifty-seven".