217930990 has 32 divisors (see below), whose sum is σ = 425494944. Its totient is φ = 80040960.

The previous prime is 217930943. The next prime is 217930991. The reversal of 217930990 is 99039712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217930991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8664 + ... + 22603.

It is an arithmetic number, because the mean of its divisors is an integer number (13296717).

Almost surely, 2^217930990 is an apocalyptic number.

217930990 is a deficient number, since it is larger than the sum of its proper divisors (207563954).

217930990 is a wasteful number, since it uses less digits than its factorization.

217930990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31332.

The product of its (nonzero) digits is 30618, while the sum is 40.

The square root of 217930990 is about 14762.4859017714. The cubic root of 217930990 is about 601.7826520445.

The spelling of 217930990 in words is "two hundred seventeen million, nine hundred thirty thousand, nine hundred ninety".