31986145 has 4 divisors (see below), whose sum is σ = 38383380. Its totient is φ = 25588912.

The previous prime is 31986133. The next prime is 31986151. The reversal of 31986145 is 54168913.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54168913 = 41 ⋅1321193.

It can be written as a sum of positive squares in 2 ways, for example, as 6594624 + 25391521 = 2568^2 + 5039^2 .

It is a cyclic number.

It is not a de Polignac number, because 31986145 - 2⁹ = 31985633 is a prime.

It is a super-2 number, since 2×31986145² = 2046226943922050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3198610 + ... + 3198619.

It is an arithmetic number, because the mean of its divisors is an integer number (9595845).

Almost surely, 2^31986145 is an apocalyptic number.

It is an amenable number.

31986145 is a deficient number, since it is larger than the sum of its proper divisors (6397235).

31986145 is an equidigital number, since it uses as much as digits as its factorization.

31986145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6397234.

The product of its digits is 25920, while the sum is 37.

The square root of 31986145 is about 5655.6294963514. The cubic root of 31986145 is about 317.4343841093.

It can be divided in two parts, 31986 and 145, that added together give a triangular number (32131 = T₂₅₃).

The spelling of 31986145 in words is "thirty-one million, nine hundred eighty-six thousand, one hundred forty-five".