31385861 has 8 divisors (see below), whose sum is σ = 33844440. Its totient is φ = 28933632.

The previous prime is 31385819. The next prime is 31385909. The reversal of 31385861 is 16858313.

It can be written as a sum of positive squares in 4 ways, for example, as 93025 + 31292836 = 305^2 + 5594^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31385861 - 2⁶ = 31385797 is a prime.

It is a super-2 number, since 2×31385861² = 1970144541422642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31385261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15821 + ... + 17693.

It is an arithmetic number, because the mean of its divisors is an integer number (4230555).

Almost surely, 2^31385861 is an apocalyptic number.

It is an amenable number.

31385861 is a deficient number, since it is larger than the sum of its proper divisors (2458579).

31385861 is a wasteful number, since it uses less digits than its factorization.

31385861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3175.

The product of its digits is 17280, while the sum is 35.

The square root of 31385861 is about 5602.3085420209. The cubic root of 31385861 is about 315.4360669227.

The spelling of 31385861 in words is "thirty-one million, three hundred eighty-five thousand, eight hundred sixty-one".