90189581 has 4 divisors (see below), whose sum is σ = 91065312. Its totient is φ = 89313852.

The previous prime is 90189559. The next prime is 90189653. The reversal of 90189581 is 18598109.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18598109 = 31 ⋅599939.

It is a cyclic number.

It is not a de Polignac number, because 90189581 - 2²² = 85995277 is a prime.

It is a super-2 number, since 2×90189581² = 16268321041911122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90189511) 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, 437711 + ... + 437916.

It is an arithmetic number, because the mean of its divisors is an integer number (22766328).

Almost surely, 2^90189581 is an apocalyptic number.

It is an amenable number.

90189581 is a deficient number, since it is larger than the sum of its proper divisors (875731).

90189581 is a wasteful number, since it uses less digits than its factorization.

90189581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875730.

The product of its (nonzero) digits is 25920, while the sum is 41.

The square root of 90189581 is about 9496.8195202394. The cubic root of 90189581 is about 448.4549166371.

The spelling of 90189581 in words is "ninety million, one hundred eighty-nine thousand, five hundred eighty-one".