31375081 has 12 divisors (see below), whose sum is σ = 33742332. Its totient is φ = 29072384.

The previous prime is 31375051. The next prime is 31375103. The reversal of 31375081 is 18057313.

31375081 is a nontrivial binomial coefficient, being equal to C(7922, 2).

It can be written as a sum of positive squares in 6 ways, for example, as 3549456 + 27825625 = 1884^2 + 5275^2 .

It is not a de Polignac number, because 31375081 - 2⁵ = 31375049 is a prime.

It is a super-2 number, since 2×31375081² = 1968791415513122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31375031) 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, 134541 + ... + 134773.

It is an arithmetic number, because the mean of its divisors is an integer number (2811861).

Almost surely, 2^31375081 is an apocalyptic number.

31375081 is the 7921-st triangular number and also the 3961-st hexagonal number.

31375081 is the 2641-st centered nonagonal number.

It is an amenable number.

31375081 is a deficient number, since it is larger than the sum of its proper divisors (2367251).

31375081 is an equidigital number, since it uses as much as digits as its factorization.

31375081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428 (or 339 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 31375081 is about 5601.3463560112. The cubic root of 31375081 is about 315.3999488526.

The spelling of 31375081 in words is "thirty-one million, three hundred seventy-five thousand, eighty-one".