31440155 has 16 divisors (see below), whose sum is σ = 39964320. Its totient is φ = 23678208.

The previous prime is 31440127. The next prime is 31440161. The reversal of 31440155 is 55104413.

It is a cyclic number.

It is not a de Polignac number, because 31440155 - 2¹⁰ = 31439131 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31440155.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15479 + ... + 17391.

It is an arithmetic number, because the mean of its divisors is an integer number (2497770).

Almost surely, 2^31440155 is an apocalyptic number.

31440155 is a deficient number, since it is larger than the sum of its proper divisors (8524165).

31440155 is a wasteful number, since it uses less digits than its factorization.

31440155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 31440155 is about 5607.1521292007. The cubic root of 31440155 is about 315.6178517481.

Adding to 31440155 its reverse (55104413), we get a palindrome (86544568).

The spelling of 31440155 in words is "thirty-one million, four hundred forty thousand, one hundred fifty-five".