31123120213013 has 4 divisors (see below), whose sum is σ = 31350296273100. Its totient is φ = 30895944152928.

The previous prime is 31123120212953. The next prime is 31123120213069. The reversal of 31123120213013 is 31031202132113.

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 8215572503524 + 22907547709489 = 2866282^2 + 4786183^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31123120213013 is a prime.

It is a super-2 number, since 2×31123120213013² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31123120213013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31123120213313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113588029838 + ... + 113588030111.

It is an arithmetic number, because the mean of its divisors is an integer number (7837574068275).

Almost surely, 2^{31123120213013} is an apocalyptic number.

It is an amenable number.

31123120213013 is a deficient number, since it is larger than the sum of its proper divisors (227176060087).

31123120213013 is a wasteful number, since it uses less digits than its factorization.

31123120213013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227176060086.

The product of its (nonzero) digits is 648, while the sum is 23.

Adding to 31123120213013 its reverse (31031202132113), we get a palindrome (62154322345126).

The spelling of 31123120213013 in words is "thirty-one trillion, one hundred twenty-three billion, one hundred twenty million, two hundred thirteen thousand, thirteen".