209979231 has 32 divisors (see below), whose sum is σ = 350135808. Its totient is φ = 108743040.

The previous prime is 209979229. The next prime is 209979247. The reversal of 209979231 is 132979902.

It is a happy number.

It is not a de Polignac number, because 209979231 - 2¹ = 209979229 is a prime.

It is a super-2 number, since 2×209979231² = 88182554902702722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209979251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 84945 + ... + 87381.

It is an arithmetic number, because the mean of its divisors is an integer number (10941744).

Almost surely, 2^209979231 is an apocalyptic number.

209979231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

209979231 is a deficient number, since it is larger than the sum of its proper divisors (140156577).

209979231 is a wasteful number, since it uses less digits than its factorization.

209979231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2831.

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 209979231 is about 14490.6601298906. The cubic root of 209979231 is about 594.3725995009.

The spelling of 209979231 in words is "two hundred nine million, nine hundred seventy-nine thousand, two hundred thirty-one".