31217145 has 16 divisors (see below), whose sum is σ = 50032512. Its totient is φ = 16620800.

The previous prime is 31217111. The next prime is 31217149. The reversal of 31217145 is 54171213.

It is not a de Polignac number, because 31217145 - 2¹⁶ = 31151609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31217149) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9745 + ... + 12545.

It is an arithmetic number, because the mean of its divisors is an integer number (3127032).

Almost surely, 2^31217145 is an apocalyptic number.

It is an amenable number.

31217145 is a deficient number, since it is larger than the sum of its proper divisors (18815367).

31217145 is a wasteful number, since it uses less digits than its factorization.

31217145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3552.

The product of its digits is 840, while the sum is 24.

The square root of 31217145 is about 5587.2305304149. The cubic root of 31217145 is about 314.8698378831.

Adding to 31217145 its reverse (54171213), we get a palindrome (85388358).

The spelling of 31217145 in words is "thirty-one million, two hundred seventeen thousand, one hundred forty-five".