91987877 has 2 divisors, whose sum is σ = 91987878. Its totient is φ = 91987876.

The previous prime is 91987843. The next prime is 91987897. The reversal of 91987877 is 77878919.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74632321 + 17355556 = 8639^2 + 4166^2 .

It is a cyclic number.

It is not a de Polignac number, because 91987877 - 2¹² = 91983781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91987897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45993938 + 45993939.

It is an arithmetic number, because the mean of its divisors is an integer number (45993939).

Almost surely, 2^91987877 is an apocalyptic number.

It is an amenable number.

91987877 is a deficient number, since it is larger than the sum of its proper divisors (1).

91987877 is an equidigital number, since it uses as much as digits as its factorization.

91987877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1778112, while the sum is 56.

The square root of 91987877 is about 9591.0310707452. The cubic root of 91987877 is about 451.4159138520.

The spelling of 91987877 in words is "ninety-one million, nine hundred eighty-seven thousand, eight hundred seventy-seven".