31890861 has 48 divisors (see below), whose sum is σ = 51772480. Its totient is φ = 19388160.

The previous prime is 31890839. The next prime is 31890869. The reversal of 31890861 is 16809813.

It is not a de Polignac number, because 31890861 - 2⁵ = 31890829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31890869) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 475950 + ... + 476016.

Almost surely, 2^31890861 is an apocalyptic number.

It is an amenable number.

31890861 is a deficient number, since it is larger than the sum of its proper divisors (19881619).

31890861 is a wasteful number, since it uses less digits than its factorization.

31890861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 31890861 is about 5647.1993943901. The cubic root of 31890861 is about 317.1188672765.

The spelling of 31890861 in words is "thirty-one million, eight hundred ninety thousand, eight hundred sixty-one".