90181581 has 32 divisors (see below), whose sum is σ = 146534400. Its totient is φ = 48185280.

The previous prime is 90181577. The next prime is 90181589. The reversal of 90181581 is 18518109.

It is not a de Polignac number, because 90181581 - 2² = 90181577 is a prime.

It is a super-2 number, since 2×90181581² = 16265435103319122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90181589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30091 + ... + 32951.

It is an arithmetic number, because the mean of its divisors is an integer number (4579200).

Almost surely, 2^90181581 is an apocalyptic number.

It is an amenable number.

90181581 is a deficient number, since it is larger than the sum of its proper divisors (56352819).

90181581 is a wasteful number, since it uses less digits than its factorization.

90181581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2969.

The product of its (nonzero) digits is 2880, while the sum is 33.

The square root of 90181581 is about 9496.3983172569. The cubic root of 90181581 is about 448.4416566228.

The spelling of 90181581 in words is "ninety million, one hundred eighty-one thousand, five hundred eighty-one".