91561511 has 2 divisors, whose sum is σ = 91561512. Its totient is φ = 91561510.

The previous prime is 91561471. The next prime is 91561517. The reversal of 91561511 is 11516519.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91561511 - 2⁶ = 91561447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91561517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45780755 + 45780756.

It is an arithmetic number, because the mean of its divisors is an integer number (45780756).

Almost surely, 2^91561511 is an apocalyptic number.

91561511 is a deficient number, since it is larger than the sum of its proper divisors (1).

91561511 is an equidigital number, since it uses as much as digits as its factorization.

91561511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1350, while the sum is 29.

The square root of 91561511 is about 9568.7779261513. Note that the first 3 decimals coincide. The cubic root of 91561511 is about 450.7173923471.

It can be divided in two parts, 915 and 61511, that added together give a palindrome (62426).

The spelling of 91561511 in words is "ninety-one million, five hundred sixty-one thousand, five hundred eleven".