31380561 has 8 divisors (see below), whose sum is σ = 46489760. Its totient is φ = 20920356.

The previous prime is 31380541. The next prime is 31380563. The reversal of 31380561 is 16508313.

It is not a de Polignac number, because 31380561 - 2⁵ = 31380529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 1162243 = 31380561 / (3 + 1 + 3 + 8 + 0 + 5 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31380563) 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, 581095 + ... + 581148.

It is an arithmetic number, because the mean of its divisors is an integer number (5811220).

Almost surely, 2^31380561 is an apocalyptic number.

It is an amenable number.

31380561 is a deficient number, since it is larger than the sum of its proper divisors (15109199).

31380561 is a wasteful number, since it uses less digits than its factorization.

31380561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1162252 (or 1162246 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 31380561 is about 5601.8355027616. The cubic root of 31380561 is about 315.4183104636.

Adding to 31380561 its reverse (16508313), we get a palindrome (47888874).

The spelling of 31380561 in words is "thirty-one million, three hundred eighty thousand, five hundred sixty-one".