31103431621 has 4 divisors (see below), whose sum is σ = 31109893452. Its totient is φ = 31096969792.

The previous prime is 31103431609. The next prime is 31103431633. The reversal of 31103431621 is 12613430113.

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

It is an interprime number because it is at equal distance from previous prime (31103431609) and next prime (31103431633).

It can be written as a sum of positive squares in 2 ways, for example, as 8808761025 + 22294670596 = 93855^2 + 149314^2 .

It is a cyclic number.

It is not a de Polignac number, because 31103431621 - 2⁷ = 31103431493 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 (31103432621) 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, 3223690 + ... + 3233323.

It is an arithmetic number, because the mean of its divisors is an integer number (7777473363).

Almost surely, 2^31103431621 is an apocalyptic number.

It is an amenable number.

31103431621 is a deficient number, since it is larger than the sum of its proper divisors (6461831).

31103431621 is an equidigital number, since it uses as much as digits as its factorization.

31103431621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6461830.

The product of its (nonzero) digits is 1296, while the sum is 25.

Adding to 31103431621 its reverse (12613430113), we get a palindrome (43716861734).

The spelling of 31103431621 in words is "thirty-one billion, one hundred three million, four hundred thirty-one thousand, six hundred twenty-one".