90561561 has 4 divisors (see below), whose sum is σ = 120748752. Its totient is φ = 60374372.

The previous prime is 90561547. The next prime is 90561563. The reversal of 90561561 is 16516509.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 90561561 - 2⁵ = 90561529 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90561563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15093591 + ... + 15093596.

It is an arithmetic number, because the mean of its divisors is an integer number (30187188).

Almost surely, 2^90561561 is an apocalyptic number.

It is an amenable number.

90561561 is a deficient number, since it is larger than the sum of its proper divisors (30187191).

90561561 is a wasteful number, since it uses less digits than its factorization.

90561561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30187190.

The product of its (nonzero) digits is 8100, while the sum is 33.

The square root of 90561561 is about 9516.3838194978. The cubic root of 90561561 is about 449.0706102380.

The spelling of 90561561 in words is "ninety million, five hundred sixty-one thousand, five hundred sixty-one".