90221765 has 4 divisors (see below), whose sum is σ = 108266124. Its totient is φ = 72177408.

The previous prime is 90221743. The next prime is 90221773. The reversal of 90221765 is 56712209.

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 47789569 + 42432196 = 6913^2 + 6514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90221765 is a prime.

It is a Duffinian number.

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, 9022172 + ... + 9022181.

It is an arithmetic number, because the mean of its divisors is an integer number (27066531).

Almost surely, 2^90221765 is an apocalyptic number.

It is an amenable number.

90221765 is a deficient number, since it is larger than the sum of its proper divisors (18044359).

90221765 is a wasteful number, since it uses less digits than its factorization.

90221765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18044358.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 90221765 is about 9498.5138311212. The cubic root of 90221765 is about 448.5082537536.

The spelling of 90221765 in words is "ninety million, two hundred twenty-one thousand, seven hundred sixty-five".