31890871 has 4 divisors (see below), whose sum is σ = 31941112. Its totient is φ = 31840632.

The previous prime is 31890869. The next prime is 31890899. The reversal of 31890871 is 17809813.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31890871 - 2¹ = 31890869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31890871.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31890071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24156 + ... + 25441.

It is an arithmetic number, because the mean of its divisors is an integer number (7985278).

Almost surely, 2^31890871 is an apocalyptic number.

31890871 is a deficient number, since it is larger than the sum of its proper divisors (50241).

31890871 is an equidigital number, since it uses as much as digits as its factorization.

31890871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50240.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 31890871 is about 5647.2002797847. The cubic root of 31890871 is about 317.1189004227.

It can be divided in two parts, 31890 and 871, that added together give a square (32761 = 181²).

The spelling of 31890871 in words is "thirty-one million, eight hundred ninety thousand, eight hundred seventy-one".