90640881 has 6 divisors (see below), whose sum is σ = 130925730. Its totient is φ = 60427248.

The previous prime is 90640871. The next prime is 90640939. The reversal of 90640881 is 18804609.

It is a happy number.

90640881 is a `hidden beast` number, since 9 + 0 + 640 + 8 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 52707600 + 37933281 = 7260^2 + 6159^2 .

It is not a de Polignac number, because 90640881 - 2⁶ = 90640817 is a prime.

It is a super-2 number, since 2×90640881² = 16431538616912322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (90640841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5035596 + ... + 5035613.

It is an arithmetic number, because the mean of its divisors is an integer number (21820955).

Almost surely, 2^90640881 is an apocalyptic number.

It is an amenable number.

90640881 is a deficient number, since it is larger than the sum of its proper divisors (40284849).

90640881 is a wasteful number, since it uses less digits than its factorization.

90640881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10071215 (or 10071212 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 90640881 is about 9520.5504567751. The cubic root of 90640881 is about 449.2016808818.

The spelling of 90640881 in words is "ninety million, six hundred forty thousand, eight hundred eighty-one".