90991028 has 12 divisors (see below), whose sum is σ = 160450752. Its totient is φ = 45147960.

The previous prime is 90991027. The next prime is 90991031. The reversal of 90991028 is 82019909.

It is a junction number, because it is equal to n+sod(n) for n = 90990982 and 90991000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90991027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86300 + ... + 87347.

It is an arithmetic number, because the mean of its divisors is an integer number (13370896).

Almost surely, 2^90991028 is an apocalyptic number.

It is an amenable number.

90991028 is a deficient number, since it is larger than the sum of its proper divisors (69459724).

90991028 is a wasteful number, since it uses less digits than its factorization.

90991028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173782 (or 173780 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 90991028 is about 9538.9217420000. The cubic root of 90991028 is about 449.7793617960.

The spelling of 90991028 in words is "ninety million, nine hundred ninety-one thousand, twenty-eight".