31578440213 has 4 divisors (see below), whose sum is σ = 31580578860. Its totient is φ = 31576301568.

The previous prime is 31578440177. The next prime is 31578440227. The reversal of 31578440213 is 31204487513.

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 6878545969 + 24699894244 = 82937^2 + 157162^2 .

It is a cyclic number.

It is not a de Polignac number, because 31578440213 - 2⁶ = 31578440149 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 (31578440273) 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, 1047020 + ... + 1076757.

It is an arithmetic number, because the mean of its divisors is an integer number (7895144715).

Almost surely, 2^31578440213 is an apocalyptic number.

It is an amenable number.

31578440213 is a deficient number, since it is larger than the sum of its proper divisors (2138647).

31578440213 is a wasteful number, since it uses less digits than its factorization.

31578440213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138646.

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 31578440213 in words is "thirty-one billion, five hundred seventy-eight million, four hundred forty thousand, two hundred thirteen".