31225140 has 36 divisors (see below), whose sum is σ = 94716804. Its totient is φ = 8326656.

The previous prime is 31225133. The next prime is 31225147. The reversal of 31225140 is 4152213.

It is an interprime number because it is at equal distance from previous prime (31225133) and next prime (31225147).

It can be written as a sum of positive squares in 2 ways, for example, as 3283344 + 27941796 = 1812^2 + 5286^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31225147) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 86557 + ... + 86916.

Almost surely, 2^31225140 is an apocalyptic number.

31225140 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31225140 is an abundant number, since it is smaller than the sum of its proper divisors (63491664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31225140 is a wasteful number, since it uses less digits than its factorization.

31225140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173488 (or 173483 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 31225140 is about 5587.9459553578. The cubic root of 31225140 is about 314.8967159494.

Adding to 31225140 its reverse (4152213), we get a palindrome (35377353).

It can be divided in two parts, 312 and 25140, that added together give a palindrome (25452).

The spelling of 31225140 in words is "thirty-one million, two hundred twenty-five thousand, one hundred forty".