91625473809 has 81 divisors (see below), whose sum is σ = 142658294961. Its totient is φ = 58844296800.

The previous prime is 91625473789. The next prime is 91625473831. The reversal of 91625473809 is 90837452619.

The square root of 91625473809 is 302697.

It is a perfect power (a square), and thus also a powerful number.

91625473809 is a `hidden beast` number, since 9 + 1 + 6 + 254 + 7 + 380 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 68238500625 + 23386973184 = 261225^2 + 152928^2 .

It is a tau number, because it is divible by the number of its divisors (81).

It is a de Polignac number, because none of the positive numbers 2^k-91625473809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91625473909) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 907182859 + ... + 907182959.

It is a 2-persistent number, because it is pandigital, and so is 2⋅91625473809 = 183250947618, but 3⋅91625473809 = 274876421427 is not.

Almost surely, 2^91625473809 is an apocalyptic number.

91625473809 is the 302697-th square number.

91625473809 is the 151349-th centered octagonal number.

It is an amenable number.

91625473809 is a deficient number, since it is larger than the sum of its proper divisors (51032821152).

91625473809 is an frugal number, since it uses more digits than its factorization.

91625473809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The spelling of 91625473809 in words is "ninety-one billion, six hundred twenty-five million, four hundred seventy-three thousand, eight hundred nine".