91987757 has 4 divisors (see below), whose sum is σ = 94955136. Its totient is φ = 89020380.

The previous prime is 91987729. The next prime is 91987769. The reversal of 91987757 is 75778919.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91987757 - 2⁸ = 91987501 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91987699 and 91987708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91983757) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1483643 + ... + 1483704.

It is an arithmetic number, because the mean of its divisors is an integer number (23738784).

Almost surely, 2^91987757 is an apocalyptic number.

It is an amenable number.

91987757 is a deficient number, since it is larger than the sum of its proper divisors (2967379).

91987757 is a wasteful number, since it uses less digits than its factorization.

91987757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2967378.

The product of its digits is 1111320, while the sum is 53.

The square root of 91987757 is about 9591.0248148986. The cubic root of 91987757 is about 451.4157175583.

The spelling of 91987757 in words is "ninety-one million, nine hundred eighty-seven thousand, seven hundred fifty-seven".