91072031 has 4 divisors (see below), whose sum is σ = 91503864. Its totient is φ = 90640200.

The previous prime is 91072027. The next prime is 91072049. The reversal of 91072031 is 13027019.

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 91072031 - 2² = 91072027 is a prime.

It is a super-2 number, since 2×91072031² = 16588229660929922, 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 = 91071988 and 91072006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91072021) 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, 215600 + ... + 216021.

It is an arithmetic number, because the mean of its divisors is an integer number (22875966).

Almost surely, 2^91072031 is an apocalyptic number.

91072031 is a deficient number, since it is larger than the sum of its proper divisors (431833).

91072031 is a wasteful number, since it uses less digits than its factorization.

91072031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431832.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 91072031 is about 9543.1667176048. The cubic root of 91072031 is about 449.9127913308.

The spelling of 91072031 in words is "ninety-one million, seventy-two thousand, thirty-one".