90118781 has 4 divisors (see below), whose sum is σ = 90408864. Its totient is φ = 89828700.

The previous prime is 90118771. The next prime is 90118793. The reversal of 90118781 is 18781109.

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.

It is a cyclic number.

It is not a de Polignac number, because 90118781 - 2¹⁰ = 90117757 is a prime.

It is a super-2 number, since 2×90118781² = 16242789377851922, 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 (90118771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144575 + ... + 145196.

It is an arithmetic number, because the mean of its divisors is an integer number (22602216).

Almost surely, 2^90118781 is an apocalyptic number.

It is an amenable number.

90118781 is a deficient number, since it is larger than the sum of its proper divisors (290083).

90118781 is a wasteful number, since it uses less digits than its factorization.

90118781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290082.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 90118781 is about 9493.0912246749. The cubic root of 90118781 is about 448.3375382600.

The spelling of 90118781 in words is "ninety million, one hundred eighteen thousand, seven hundred eighty-one".