126372721 has 2 divisors, whose sum is σ = 126372722. Its totient is φ = 126372720.

The previous prime is 126372689. The next prime is 126372751. The reversal of 126372721 is 127273621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126315121 + 57600 = 11239^2 + 240^2 .

It is an emirp because it is prime and its reverse (127273621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126372721 - 2⁵ = 126372689 is a prime.

It is a super-2 number, since 2×126372721² = 31940129225887682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (126372751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63186360 + 63186361.

It is an arithmetic number, because the mean of its divisors is an integer number (63186361).

Almost surely, 2^126372721 is an apocalyptic number.

It is an amenable number.

126372721 is a deficient number, since it is larger than the sum of its proper divisors (1).

126372721 is an equidigital number, since it uses as much as digits as its factorization.

126372721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7056, while the sum is 31.

The square root of 126372721 is about 11241.5622135004. The cubic root of 126372721 is about 501.8236352890.

It can be divided in two parts, 1263 and 72721, that added together give a square (73984 = 272²).

The spelling of 126372721 in words is "one hundred twenty-six million, three hundred seventy-two thousand, seven hundred twenty-one".