91415521 has 2 divisors, whose sum is σ = 91415522. Its totient is φ = 91415520.

The previous prime is 91415507. The next prime is 91415543. The reversal of 91415521 is 12551419.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54982225 + 36433296 = 7415^2 + 6036^2 .

It is a cyclic number.

It is not a de Polignac number, because 91415521 - 2¹¹ = 91413473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91415521.

It is not a weakly prime, because it can be changed into another prime (91415591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45707760 + 45707761.

It is an arithmetic number, because the mean of its divisors is an integer number (45707761).

Almost surely, 2^91415521 is an apocalyptic number.

It is an amenable number.

91415521 is a deficient number, since it is larger than the sum of its proper divisors (1).

91415521 is an equidigital number, since it uses as much as digits as its factorization.

91415521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The square root of 91415521 is about 9561.1464270766. The cubic root of 91415521 is about 450.4777165486.

The spelling of 91415521 in words is "ninety-one million, four hundred fifteen thousand, five hundred twenty-one".