31249945 has 4 divisors (see below), whose sum is σ = 37499940. Its totient is φ = 24999952.

The previous prime is 31249943. The next prime is 31249957. The reversal of 31249945 is 54994213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54994213 = 3929 ⋅13997.

It can be written as a sum of positive squares in 2 ways, for example, as 23348224 + 7901721 = 4832^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 31249945 - 2¹ = 31249943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31249943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3124990 + ... + 3124999.

It is an arithmetic number, because the mean of its divisors is an integer number (9374985).

Almost surely, 2^31249945 is an apocalyptic number.

It is an amenable number.

31249945 is a deficient number, since it is larger than the sum of its proper divisors (6249995).

31249945 is an equidigital number, since it uses as much as digits as its factorization.

31249945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6249994.

The product of its digits is 38880, while the sum is 37.

The square root of 31249945 is about 5590.1650243978. The cubic root of 31249945 is about 314.9800776852.

The spelling of 31249945 in words is "thirty-one million, two hundred forty-nine thousand, nine hundred forty-five".