91501681 has 2 divisors, whose sum is σ = 91501682. Its totient is φ = 91501680.

The previous prime is 91501673. The next prime is 91501723. The reversal of 91501681 is 18610519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89586225 + 1915456 = 9465^2 + 1384^2 .

It is a cyclic number.

It is not a de Polignac number, because 91501681 - 2³ = 91501673 is a prime.

It is a super-2 number, since 2×91501681² = 16745115251651522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91501601) 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 as a sum of consecutive naturals, namely, 45750840 + 45750841.

It is an arithmetic number, because the mean of its divisors is an integer number (45750841).

Almost surely, 2^91501681 is an apocalyptic number.

It is an amenable number.

91501681 is a deficient number, since it is larger than the sum of its proper divisors (1).

91501681 is an equidigital number, since it uses as much as digits as its factorization.

91501681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 31.

The square root of 91501681 is about 9565.6511017285. The cubic root of 91501681 is about 450.6191986226.

The spelling of 91501681 in words is "ninety-one million, five hundred one thousand, six hundred eighty-one".