91000675721 has 2 divisors, whose sum is σ = 91000675722. Its totient is φ = 91000675720.

The previous prime is 91000675709. The next prime is 91000675771. The reversal of 91000675721 is 12757600019.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80213568400 + 10787107321 = 283220^2 + 103861^2 .

It is a cyclic number.

It is not a de Polignac number, because 91000675721 - 2¹⁸ = 91000413577 is a prime.

It is a super-2 number, since 2×91000675721² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91000675771) 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, 45500337860 + 45500337861.

It is an arithmetic number, because the mean of its divisors is an integer number (45500337861).

Almost surely, 2^91000675721 is an apocalyptic number.

It is an amenable number.

91000675721 is a deficient number, since it is larger than the sum of its proper divisors (1).

91000675721 is an equidigital number, since it uses as much as digits as its factorization.

91000675721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26460, while the sum is 38.

The spelling of 91000675721 in words is "ninety-one billion, six hundred seventy-five thousand, seven hundred twenty-one".