31540013 has 2 divisors, whose sum is σ = 31540014. Its totient is φ = 31540012.

The previous prime is 31540009. The next prime is 31540031. The reversal of 31540013 is 31004513.

Together with next prime (31540031) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31382404 + 157609 = 5602^2 + 397^2 .

It is an emirp because it is prime and its reverse (31004513) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31540013 - 2² = 31540009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31539973 and 31540000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31540063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15770006 + 15770007.

It is an arithmetic number, because the mean of its divisors is an integer number (15770007).

Almost surely, 2^31540013 is an apocalyptic number.

It is an amenable number.

31540013 is a deficient number, since it is larger than the sum of its proper divisors (1).

31540013 is an equidigital number, since it uses as much as digits as its factorization.

31540013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 31540013 is about 5616.0495902369. The cubic root of 31540013 is about 315.9516463161.

Adding to 31540013 its reverse (31004513), we get a palindrome (62544526).

The spelling of 31540013 in words is "thirty-one million, five hundred forty thousand, thirteen".