31309057 has 4 divisors (see below), whose sum is σ = 33717460. Its totient is φ = 28900656.

The previous prime is 31309037. The next prime is 31309063. The reversal of 31309057 is 75090313.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75090313 = 191 ⋅393143.

It can be written as a sum of positive squares in 2 ways, for example, as 18284176 + 13024881 = 4276^2 + 3609^2 .

It is a cyclic number.

It is not a de Polignac number, because 31309057 - 2²³ = 22920449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31309007) 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, 1204182 + ... + 1204207.

It is an arithmetic number, because the mean of its divisors is an integer number (8429365).

Almost surely, 2^31309057 is an apocalyptic number.

It is an amenable number.

31309057 is a deficient number, since it is larger than the sum of its proper divisors (2408403).

31309057 is a wasteful number, since it uses less digits than its factorization.

31309057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2408402.

The product of its (nonzero) digits is 2835, while the sum is 28.

The square root of 31309057 is about 5595.4496691508. The cubic root of 31309057 is about 315.1785566989.

The spelling of 31309057 in words is "thirty-one million, three hundred nine thousand, fifty-seven".