90909090978 has 32 divisors (see below), whose sum is σ = 183602350080. Its totient is φ = 30006587520.

The previous prime is 90909090977. The next prime is 90909091027. The reversal of 90909090978 is 87909090909.

It is not an unprimeable number, because it can be changed into a prime (90909090977) 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, 282508 + ... + 511496.

It is an arithmetic number, because the mean of its divisors is an integer number (5737573440).

Almost surely, 2^90909090978 is an apocalyptic number.

90909090978 is an abundant number, since it is smaller than the sum of its proper divisors (92693259102).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

90909090978 is a wasteful number, since it uses less digits than its factorization.

90909090978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229642.

The product of its (nonzero) digits is 3306744, while the sum is 60.

The spelling of 90909090978 in words is "ninety billion, nine hundred nine million, ninety thousand, nine hundred seventy-eight".