91072391 has 8 divisors (see below), whose sum is σ = 94065840. Its totient is φ = 88126272.

The previous prime is 91072369. The next prime is 91072411. The reversal of 91072391 is 19327019.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 91072391 - 2¹⁰ = 91071367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91072321) 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, 7901 + ... + 15638.

It is an arithmetic number, because the mean of its divisors is an integer number (11758230).

Almost surely, 2^91072391 is an apocalyptic number.

91072391 is a deficient number, since it is larger than the sum of its proper divisors (2993449).

91072391 is a wasteful number, since it uses less digits than its factorization.

91072391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23665.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 91072391 is about 9543.1855792497. The cubic root of 91072391 is about 449.9133841523.

The spelling of 91072391 in words is "ninety-one million, seventy-two thousand, three hundred ninety-one".