91381481 has 4 divisors (see below), whose sum is σ = 91706964. Its totient is φ = 91056000.

The previous prime is 91381439. The next prime is 91381513. The reversal of 91381481 is 18418319.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 52693081 + 38688400 = 7259^2 + 6220^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91381481 is a prime.

It is a super-2 number, since 2×91381481² = 16701150139506722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91381421) 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, 162320 + ... + 162881.

It is an arithmetic number, because the mean of its divisors is an integer number (22926741).

Almost surely, 2^91381481 is an apocalyptic number.

It is an amenable number.

91381481 is a deficient number, since it is larger than the sum of its proper divisors (325483).

91381481 is a wasteful number, since it uses less digits than its factorization.

91381481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325482.

The product of its digits is 6912, while the sum is 35.

The square root of 91381481 is about 9559.3661400744. The cubic root of 91381481 is about 450.4217954643.

The spelling of 91381481 in words is "ninety-one million, three hundred eighty-one thousand, four hundred eighty-one".