209961031 has 6 divisors (see below), whose sum is σ = 244240440. Its totient is φ = 179966556.

The previous prime is 209961023. The next prime is 209961091. The reversal of 209961031 is 130169902.

It is not a de Polignac number, because 209961031 - 2³ = 209961023 is a prime.

It is a super-2 number, since 2×209961031² = 88167269077165922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 209960984 and 209961002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209961091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2142411 + ... + 2142508.

It is an arithmetic number, because the mean of its divisors is an integer number (40706740).

Almost surely, 2^209961031 is an apocalyptic number.

209961031 is a deficient number, since it is larger than the sum of its proper divisors (34279409).

209961031 is an equidigital number, since it uses as much as digits as its factorization.

209961031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4284933 (or 4284926 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 209961031 is about 14490.0321255683. The cubic root of 209961031 is about 594.3554265424.

The spelling of 209961031 in words is "two hundred nine million, nine hundred sixty-one thousand, thirty-one".