31997205 has 12 divisors (see below), whose sum is σ = 55461900. Its totient is φ = 17065152.

The previous prime is 31997201. The next prime is 31997221. The reversal of 31997205 is 50279913.

It can be written as a sum of positive squares in 2 ways, for example, as 24980004 + 7017201 = 4998^2 + 2649^2 .

It is not a de Polignac number, because 31997205 - 2² = 31997201 is a prime.

It is a super-2 number, since 2×31997205² = 2047642255624050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31997205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997201) 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 11 ways as a sum of consecutive naturals, for example, 355480 + ... + 355569.

It is an arithmetic number, because the mean of its divisors is an integer number (4621825).

Almost surely, 2^31997205 is an apocalyptic number.

It is an amenable number.

31997205 is a deficient number, since it is larger than the sum of its proper divisors (23464695).

31997205 is a wasteful number, since it uses less digits than its factorization.

31997205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711060 (or 711057 counting only the distinct ones).

The product of its (nonzero) digits is 17010, while the sum is 36.

The square root of 31997205 is about 5656.6071986660. The cubic root of 31997205 is about 317.4709668205.

It can be divided in two parts, 3199 and 7205, that added together give a square (10404 = 102²).

The spelling of 31997205 in words is "thirty-one million, nine hundred ninety-seven thousand, two hundred five".