91257381 has 8 divisors (see below), whose sum is σ = 135196160. Its totient is φ = 60838236.

The previous prime is 91257367. The next prime is 91257391. The reversal of 91257381 is 18375219.

91257381 is a `hidden beast` number, since 9 + 1 + 2 + 573 + 81 = 666.

It is not a de Polignac number, because 91257381 - 2¹³ = 91249189 is a prime.

It is a super-2 number, since 2×91257381² = 16655819173958322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91257391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1689925 + ... + 1689978.

It is an arithmetic number, because the mean of its divisors is an integer number (16899520).

Almost surely, 2^91257381 is an apocalyptic number.

It is an amenable number.

91257381 is a deficient number, since it is larger than the sum of its proper divisors (43938779).

91257381 is a wasteful number, since it uses less digits than its factorization.

91257381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3379912 (or 3379906 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 91257381 is about 9552.8729186565. The cubic root of 91257381 is about 450.2178056734.

The spelling of 91257381 in words is "ninety-one million, two hundred fifty-seven thousand, three hundred eighty-one".