90815581 has 8 divisors (see below), whose sum is σ = 96289344. Its totient is φ = 85356480.

The previous prime is 90815567. The next prime is 90815591. The reversal of 90815581 is 18551809.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 90815581 - 2⁷ = 90815453 is a prime.

It is a super-3 number, since 3×90815581³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 90815581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90815521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10746 + ... + 17236.

It is an arithmetic number, because the mean of its divisors is an integer number (12036168).

Almost surely, 2^90815581 is an apocalyptic number.

It is an amenable number.

90815581 is a deficient number, since it is larger than the sum of its proper divisors (5473763).

90815581 is a wasteful number, since it uses less digits than its factorization.

90815581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7331.

The product of its (nonzero) digits is 14400, while the sum is 37.

The square root of 90815581 is about 9529.7209298069. The cubic root of 90815581 is about 449.4900907366.

The spelling of 90815581 in words is "ninety million, eight hundred fifteen thousand, five hundred eighty-one".