31605225 has 24 divisors (see below), whose sum is σ = 53246592. Its totient is φ = 16536000.

The previous prime is 31605221. The next prime is 31605229. The reversal of 31605225 is 52250613.

31605225 is a nontrivial binomial coefficient, being equal to C(7951, 2).

It is an interprime number because it is at equal distance from previous prime (31605221) and next prime (31605229).

It is not a de Polignac number, because 31605225 - 2² = 31605221 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31605195 and 31605204.

It is not an unprimeable number, because it can be changed into a prime (31605221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1 + ... + 7950.

It is an arithmetic number, because the mean of its divisors is an integer number (2218608).

Almost surely, 2^31605225 is an apocalyptic number.

31605225 is the 7950-th triangular number.

It is an amenable number.

31605225 is a deficient number, since it is larger than the sum of its proper divisors (21641367).

31605225 is a wasteful number, since it uses less digits than its factorization.

31605225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8017 (or 8012 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 31605225 is about 5621.8524527063. The cubic root of 31605225 is about 316.1692498505.

Adding to 31605225 its reverse (52250613), we get a palindrome (83855838).

It can be divided in two parts, 3160 and 5225, that added together give a triangular number (8385 = T₁₂₉).

The spelling of 31605225 in words is "thirty-one million, six hundred five thousand, two hundred twenty-five".