31218769612729 has 2 divisors, whose sum is σ = 31218769612730. Its totient is φ = 31218769612728.

The previous prime is 31218769612703. The next prime is 31218769612817. The reversal of 31218769612729 is 92721696781213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24259831132329 + 6958938480400 = 4925427^2 + 2637980^2 .

It is an emirp because it is prime and its reverse (92721696781213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31218769612729 - 2¹³ = 31218769604537 is a prime.

It is a super-2 number, since 2×31218769612729² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31218769612829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15609384806364 + 15609384806365.

It is an arithmetic number, because the mean of its divisors is an integer number (15609384806365).

Almost surely, 2^{31218769612729} is an apocalyptic number.

It is an amenable number.

31218769612729 is a deficient number, since it is larger than the sum of its proper divisors (1).

31218769612729 is an equidigital number, since it uses as much as digits as its factorization.

31218769612729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27433728, while the sum is 64.

The spelling of 31218769612729 in words is "thirty-one trillion, two hundred eighteen billion, seven hundred sixty-nine million, six hundred twelve thousand, seven hundred twenty-nine".