91816631 has 4 divisors (see below), whose sum is σ = 92433000. Its totient is φ = 91200264.

The previous prime is 91816619. The next prime is 91816649. The reversal of 91816631 is 13661819.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13661819 = 47 ⋅290677.

It is a cyclic number.

It is not a de Polignac number, because 91816631 - 2¹⁸ = 91554487 is a prime.

It is a super-2 number, since 2×91816631² = 16860587456380322, 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 = 91816591 and 91816600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91815631) 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, 307961 + ... + 308258.

It is an arithmetic number, because the mean of its divisors is an integer number (23108250).

Almost surely, 2^91816631 is an apocalyptic number.

91816631 is a deficient number, since it is larger than the sum of its proper divisors (616369).

91816631 is a wasteful number, since it uses less digits than its factorization.

91816631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616368.

The product of its digits is 7776, while the sum is 35.

The square root of 91816631 is about 9582.0995089803. The cubic root of 91816631 is about 451.1356189865.

The spelling of 91816631 in words is "ninety-one million, eight hundred sixteen thousand, six hundred thirty-one".