31390 has 16 divisors (see below), whose sum is σ = 58608. Its totient is φ = 12096.

The previous prime is 31387. The next prime is 31391. The reversal of 31390 is 9313.

31390 = 3² + 4² + ... + 45².

It is a happy number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31391) 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, 394 + ... + 466.

It is an arithmetic number, because the mean of its divisors is an integer number (3663).

2³¹³⁹⁰ is an apocalyptic number.

31390 is a deficient number, since it is larger than the sum of its proper divisors (27218).

31390 is a wasteful number, since it uses less digits than its factorization.

31390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123.

The product of its (nonzero) digits is 81, while the sum is 16.

The square root of 31390 is about 177.1722325874. The cubic root of 31390 is about 31.5449932322.

It can be divided in two parts, 31 and 390, that multiplied together give a triangular number (12090 = T₁₅₅).

The spelling of 31390 in words is "thirty-one thousand, three hundred ninety".