31520123213 has 8 divisors (see below), whose sum is σ = 32422895736. Its totient is φ = 30623731200.

The previous prime is 31520123209. The next prime is 31520123227. The reversal of 31520123213 is 31232102513.

It can be written as a sum of positive squares in 4 ways, for example, as 5786188489 + 25733934724 = 76067^2 + 160418^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31520123213 - 2² = 31520123209 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 (31520123273) 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, 1585106 + ... + 1604867.

It is an arithmetic number, because the mean of its divisors is an integer number (4052861967).

Almost surely, 2^31520123213 is an apocalyptic number.

It is an amenable number.

31520123213 is a deficient number, since it is larger than the sum of its proper divisors (902772523).

31520123213 is a wasteful number, since it uses less digits than its factorization.

31520123213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3190255.

The product of its (nonzero) digits is 1080, while the sum is 23.

Adding to 31520123213 its reverse (31232102513), we get a palindrome (62752225726).

The spelling of 31520123213 in words is "thirty-one billion, five hundred twenty million, one hundred twenty-three thousand, two hundred thirteen".