91606557751 has 4 divisors (see below), whose sum is σ = 94765404600. Its totient is φ = 88447710904.

The previous prime is 91606557727. The next prime is 91606557793. The reversal of 91606557751 is 15775560619.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 91606557751 - 2¹⁷ = 91606426679 is a prime.

It is a super-2 number, since 2×91606557751² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91606527751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1579423381 + ... + 1579423438.

It is an arithmetic number, because the mean of its divisors is an integer number (23691351150).

Almost surely, 2^91606557751 is an apocalyptic number.

91606557751 is a deficient number, since it is larger than the sum of its proper divisors (3158846849).

91606557751 is a wasteful number, since it uses less digits than its factorization.

91606557751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3158846848.

The product of its (nonzero) digits is 1984500, while the sum is 52.

The spelling of 91606557751 in words is "ninety-one billion, six hundred six million, five hundred fifty-seven thousand, seven hundred fifty-one".