30991090 has 32 divisors (see below), whose sum is σ = 63241920.
Its totient is φ = 10839744.
The previous prime is 30991067. The next prime is 30991091. The reversal of 30991090 is 9019903.
Subtracting from 30991090 its product of nonzero digits (2187), we obtain a palindrome (30988903).
It is not an unprimeable number, because it can be changed into a prime (30991091) 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, 3804 + ... + 8743.
It is an arithmetic number, because the mean of its divisors is an integer number (1976310).
Almost surely, 230991090 is an apocalyptic number.
30991090 is an abundant number, since it is smaller than the sum of its proper divisors (32250830).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
30991090 is a wasteful number, since it uses less digits than its factorization.
30991090 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 12586.
The product of its (nonzero) digits is 2187, while the sum is 31.
The square root of 30991090 is about 5566.9641637072.
The cubic root of 30991090 is about 314.1079659019.
The spelling of 30991090 in words is "thirty million, nine hundred ninety-one thousand, ninety".