31244320013 has 4 divisors (see below), whose sum is σ = 31257924540. Its totient is φ = 31230715488.

The previous prime is 31244320001. The next prime is 31244320057. The reversal of 31244320013 is 31002344213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21404275204 + 9840044809 = 146302^2 + 99197^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31244320013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31244328013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6798818 + ... + 6803411.

It is an arithmetic number, because the mean of its divisors is an integer number (7814481135).

Almost surely, 2^31244320013 is an apocalyptic number.

It is an amenable number.

31244320013 is a deficient number, since it is larger than the sum of its proper divisors (13604527).

31244320013 is a wasteful number, since it uses less digits than its factorization.

31244320013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13604526.

The product of its (nonzero) digits is 1728, while the sum is 23.

Adding to 31244320013 its reverse (31002344213), we get a palindrome (62246664226).

The spelling of 31244320013 in words is "thirty-one billion, two hundred forty-four million, three hundred twenty thousand, thirteen".