31540221205 has 4 divisors (see below), whose sum is σ = 37848265452. Its totient is φ = 25232176960.

The previous prime is 31540221191. The next prime is 31540221263. The reversal of 31540221205 is 50212204513.

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 17337778929 + 14202442276 = 131673^2 + 119174^2 .

It is not a de Polignac number, because 31540221205 - 2²¹ = 31538124053 is a prime.

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 31540221205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3154022116 + ... + 3154022125.

It is an arithmetic number, because the mean of its divisors is an integer number (9462066363).

Almost surely, 2^31540221205 is an apocalyptic number.

It is an amenable number.

31540221205 is a deficient number, since it is larger than the sum of its proper divisors (6308044247).

31540221205 is an equidigital number, since it uses as much as digits as its factorization.

31540221205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6308044246.

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 31540221205 its reverse (50212204513), we get a palindrome (81752425718).

The spelling of 31540221205 in words is "thirty-one billion, five hundred forty million, two hundred twenty-one thousand, two hundred five".