90857981 has 16 divisors (see below), whose sum is σ = 100310400. Its totient is φ = 81911808.

The previous prime is 90857947. The next prime is 90857983. The reversal of 90857981 is 18975809.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90857981 is a prime.

It is a super-2 number, since 2×90857981² = 16510345422792722, 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 (90857983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111905 + ... + 112713.

It is an arithmetic number, because the mean of its divisors is an integer number (6269400).

Almost surely, 2^90857981 is an apocalyptic number.

It is an amenable number.

90857981 is a deficient number, since it is larger than the sum of its proper divisors (9452419).

90857981 is a wasteful number, since it uses less digits than its factorization.

90857981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108.

The product of its (nonzero) digits is 181440, while the sum is 47.

The square root of 90857981 is about 9531.9452893940. The cubic root of 90857981 is about 449.5600325330.

The spelling of 90857981 in words is "ninety million, eight hundred fifty-seven thousand, nine hundred eighty-one".