126721613 has 2 divisors, whose sum is σ = 126721614. Its totient is φ = 126721612.

The previous prime is 126721603. The next prime is 126721631. The reversal of 126721613 is 316127621.

Together with next prime (126721631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 125507209 + 1214404 = 11203^2 + 1102^2 .

It is an emirp because it is prime and its reverse (316127621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126721613 - 2⁴ = 126721597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126721603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63360806 + 63360807.

It is an arithmetic number, because the mean of its divisors is an integer number (63360807).

Almost surely, 2^126721613 is an apocalyptic number.

It is an amenable number.

126721613 is a deficient number, since it is larger than the sum of its proper divisors (1).

126721613 is an equidigital number, since it uses as much as digits as its factorization.

126721613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 126721613 is about 11257.0694676723. The cubic root of 126721613 is about 502.2850254099.

The spelling of 126721613 in words is "one hundred twenty-six million, seven hundred twenty-one thousand, six hundred thirteen".