91251605 has 4 divisors (see below), whose sum is σ = 109501932. Its totient is φ = 73001280.

The previous prime is 91251599. The next prime is 91251613. The reversal of 91251605 is 50615219.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50615219 = 31 ⋅1632749.

It can be written as a sum of positive squares in 2 ways, for example, as 22676644 + 68574961 = 4762^2 + 8281^2 .

It is not a de Polignac number, because 91251605 - 2⁶ = 91251541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9125156 + ... + 9125165.

It is an arithmetic number, because the mean of its divisors is an integer number (27375483).

Almost surely, 2^91251605 is an apocalyptic number.

It is an amenable number.

91251605 is a deficient number, since it is larger than the sum of its proper divisors (18250327).

91251605 is a wasteful number, since it uses less digits than its factorization.

91251605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18250326.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 91251605 is about 9552.5705964416. The cubic root of 91251605 is about 450.2083068512.

The spelling of 91251605 in words is "ninety-one million, two hundred fifty-one thousand, six hundred five".