91131293021 has 8 divisors (see below), whose sum is σ = 92510015160. Its totient is φ = 89756093952.

The previous prime is 91131292997. The next prime is 91131293041. The reversal of 91131293021 is 12039213119.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2276625796 + 88854667225 = 47714^2 + 298085^2 .

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 91131293021 - 2¹⁰ = 91131291997 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 (91131293041) 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, 828620 + ... + 932133.

It is an arithmetic number, because the mean of its divisors is an integer number (11563751895).

Almost surely, 2^91131293021 is an apocalyptic number.

It is an amenable number.

91131293021 is a deficient number, since it is larger than the sum of its proper divisors (1378722139).

91131293021 is a wasteful number, since it uses less digits than its factorization.

91131293021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1761535.

The product of its (nonzero) digits is 2916, while the sum is 32.

The spelling of 91131293021 in words is "ninety-one billion, one hundred thirty-one million, two hundred ninety-three thousand, twenty-one".