91801631 has 4 divisors (see below), whose sum is σ = 92833200. Its totient is φ = 90770064.

The previous prime is 91801621. The next prime is 91801637. The reversal of 91801631 is 13610819.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91801631 - 2²² = 87607327 is a prime.

It is a super-2 number, since 2×91801631² = 16855078908520322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91801594 and 91801603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91801637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 515651 + ... + 515828.

It is an arithmetic number, because the mean of its divisors is an integer number (23208300).

Almost surely, 2^91801631 is an apocalyptic number.

91801631 is a deficient number, since it is larger than the sum of its proper divisors (1031569).

91801631 is a wasteful number, since it uses less digits than its factorization.

91801631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031568.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 91801631 is about 9581.3167675430. The cubic root of 91801631 is about 451.1110504425. Note that the first 3 decimals are identical.

The spelling of 91801631 in words is "ninety-one million, eight hundred one thousand, six hundred thirty-one".