91021707 has 12 divisors (see below), whose sum is σ = 150258160. Its totient is φ = 52012368.

The previous prime is 91021703. The next prime is 91021709. The reversal of 91021707 is 70712019.

It is not a de Polignac number, because 91021707 - 2² = 91021703 is a prime.

It is a super-2 number, since 2×91021707² = 16569902290387698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91021703) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 722332 + ... + 722457.

Almost surely, 2^91021707 is an apocalyptic number.

91021707 is a deficient number, since it is larger than the sum of its proper divisors (59236453).

91021707 is a wasteful number, since it uses less digits than its factorization.

91021707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1444802 (or 1444799 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 91021707 is about 9540.5297022754. The cubic root of 91021707 is about 449.8299060853.

The spelling of 91021707 in words is "ninety-one million, twenty-one thousand, seven hundred seven".