91997405653 has 4 divisors (see below), whose sum is σ = 94483822060. Its totient is φ = 89510989248.

The previous prime is 91997405627. The next prime is 91997405707. The reversal of 91997405653 is 35650479919.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 35650479919 = 383 ⋅93082193.

It can be written as a sum of positive squares in 2 ways, for example, as 61701566404 + 30295839249 = 248398^2 + 174057^2 .

It is a cyclic number.

It is not a de Polignac number, because 91997405653 - 2¹⁷ = 91997274581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91997405453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1243208148 + ... + 1243208221.

It is an arithmetic number, because the mean of its divisors is an integer number (23620955515).

Almost surely, 2^91997405653 is an apocalyptic number.

It is an amenable number.

91997405653 is a deficient number, since it is larger than the sum of its proper divisors (2486416407).

91997405653 is a wasteful number, since it uses less digits than its factorization.

91997405653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486416406.

The product of its (nonzero) digits is 9185400, while the sum is 58.

The spelling of 91997405653 in words is "ninety-one billion, nine hundred ninety-seven million, four hundred five thousand, six hundred fifty-three".