91981649 has 8 divisors (see below), whose sum is σ = 96768000. Its totient is φ = 87302992.

The previous prime is 91981639. The next prime is 91981651. The reversal of 91981649 is 94618919.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 91981649 - 2⁴ = 91981633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91981639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25169 + ... + 28590.

It is an arithmetic number, because the mean of its divisors is an integer number (12096000).

Almost surely, 2^91981649 is an apocalyptic number.

It is an amenable number.

91981649 is a deficient number, since it is larger than the sum of its proper divisors (4786351).

91981649 is a wasteful number, since it uses less digits than its factorization.

91981649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53847.

The product of its digits is 139968, while the sum is 47.

The square root of 91981649 is about 9590.7063869144. The cubic root of 91981649 is about 451.4057259814.

The spelling of 91981649 in words is "ninety-one million, nine hundred eighty-one thousand, six hundred forty-nine".