91620205 has 4 divisors (see below), whose sum is σ = 109944252. Its totient is φ = 73296160.

The previous prime is 91620173. The next prime is 91620233. The reversal of 91620205 is 50202619.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15634116 + 75986089 = 3954^2 + 8717^2 .

It is not a de Polignac number, because 91620205 - 2⁵ = 91620173 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91620205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9162016 + ... + 9162025.

It is an arithmetic number, because the mean of its divisors is an integer number (27486063).

Almost surely, 2^91620205 is an apocalyptic number.

It is an amenable number.

91620205 is a deficient number, since it is larger than the sum of its proper divisors (18324047).

91620205 is a wasteful number, since it uses less digits than its factorization.

91620205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18324046.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 91620205 is about 9571.8443886223. The cubic root of 91620205 is about 450.8136800981.

The spelling of 91620205 in words is "ninety-one million, six hundred twenty thousand, two hundred five".