31231775329121 has 2 divisors, whose sum is σ = 31231775329122. Its totient is φ = 31231775329120.

The previous prime is 31231775329093. The next prime is 31231775329123. The reversal of 31231775329121 is 12192357713213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24693833165521 + 6537942163600 = 4969289^2 + 2556940^2 .

It is an emirp because it is prime and its reverse (12192357713213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231775329121 is a prime.

It is a super-2 number, since 2×31231775329121² (a number of 28 digits) contains 22 as substring.

Together with 31231775329123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31231775329123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615887664560 + 15615887664561.

It is an arithmetic number, because the mean of its divisors is an integer number (15615887664561).

Almost surely, 2^{31231775329121} is an apocalyptic number.

It is an amenable number.

31231775329121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231775329121 is an equidigital number, since it uses as much as digits as its factorization.

31231775329121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 47.

The spelling of 31231775329121 in words is "thirty-one trillion, two hundred thirty-one billion, seven hundred seventy-five million, three hundred twenty-nine thousand, one hundred twenty-one".