91521379 has 2 divisors, whose sum is σ = 91521380. Its totient is φ = 91521378.

The previous prime is 91521373. The next prime is 91521401. The reversal of 91521379 is 97312519.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91521379 - 2⁹ = 91520867 is a prime.

It is not a weakly prime, because it can be changed into another prime (91521373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45760689 + 45760690.

It is an arithmetic number, because the mean of its divisors is an integer number (45760690).

Almost surely, 2^91521379 is an apocalyptic number.

91521379 is a deficient number, since it is larger than the sum of its proper divisors (1).

91521379 is an equidigital number, since it uses as much as digits as its factorization.

91521379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17010, while the sum is 37.

The square root of 91521379 is about 9566.6806678179. The cubic root of 91521379 is about 450.6515319452.

The spelling of 91521379 in words is "ninety-one million, five hundred twenty-one thousand, three hundred seventy-nine".