13237678721 has 2 divisors, whose sum is σ = 13237678722. Its totient is φ = 13237678720.

The previous prime is 13237678717. The next prime is 13237678787. The reversal of 13237678721 is 12787673231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12466839025 + 770839696 = 111655^2 + 27764^2 .

It is a cyclic number.

It is not a de Polignac number, because 13237678721 - 2² = 13237678717 is a prime.

It is a super-2 number, since 2×13237678721² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13237675721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6618839360 + 6618839361.

It is an arithmetic number, because the mean of its divisors is an integer number (6618839361).

Almost surely, 2^13237678721 is an apocalyptic number.

It is an amenable number.

13237678721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13237678721 is an equidigital number, since it uses as much as digits as its factorization.

13237678721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 592704, while the sum is 47.

The spelling of 13237678721 in words is "thirteen billion, two hundred thirty-seven million, six hundred seventy-eight thousand, seven hundred twenty-one".