126304721 has 4 divisors (see below), whose sum is σ = 126856500. Its totient is φ = 125752944.

The previous prime is 126304697. The next prime is 126304741. The reversal of 126304721 is 127403621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 56415121 + 69889600 = 7511^2 + 8360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126304721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126304741) 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 in 3 ways as a sum of consecutive naturals, for example, 275546 + ... + 276003.

It is an arithmetic number, because the mean of its divisors is an integer number (31714125).

Almost surely, 2^126304721 is an apocalyptic number.

It is an amenable number.

126304721 is a deficient number, since it is larger than the sum of its proper divisors (551779).

126304721 is an equidigital number, since it uses as much as digits as its factorization.

126304721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551778.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 126304721 is about 11238.5373158610. The cubic root of 126304721 is about 501.7336102441.

The spelling of 126304721 in words is "one hundred twenty-six million, three hundred four thousand, seven hundred twenty-one".