91970589721 has 2 divisors, whose sum is σ = 91970589722. Its totient is φ = 91970589720.

The previous prime is 91970589691. The next prime is 91970589731. The reversal of 91970589721 is 12798507919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63788574096 + 28182015625 = 252564^2 + 167875^2 .

It is a cyclic number.

It is not a de Polignac number, because 91970589721 - 2¹³ = 91970581529 is a prime.

It is a super-3 number, since 3×91970589721³ (a number of 34 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (91970589731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45985294860 + 45985294861.

It is an arithmetic number, because the mean of its divisors is an integer number (45985294861).

Almost surely, 2^91970589721 is an apocalyptic number.

It is an amenable number.

91970589721 is a deficient number, since it is larger than the sum of its proper divisors (1).

91970589721 is an equidigital number, since it uses as much as digits as its factorization.

91970589721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2857680, while the sum is 58.

The spelling of 91970589721 in words is "ninety-one billion, nine hundred seventy million, five hundred eighty-nine thousand, seven hundred twenty-one".