126549721 has 4 divisors (see below), whose sum is σ = 126584500. Its totient is φ = 126514944.

The previous prime is 126549713. The next prime is 126549727. The reversal of 126549721 is 127945621.

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 27825625 + 98724096 = 5275^2 + 9936^2 .

It is a cyclic number.

It is not a de Polignac number, because 126549721 - 2³ = 126549713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126549727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11196 + ... + 19453.

It is an arithmetic number, because the mean of its divisors is an integer number (31646125).

Almost surely, 2^126549721 is an apocalyptic number.

It is an amenable number.

126549721 is a deficient number, since it is larger than the sum of its proper divisors (34779).

126549721 is an equidigital number, since it uses as much as digits as its factorization.

126549721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34778.

The product of its digits is 30240, while the sum is 37.

The square root of 126549721 is about 11249.4320301071. The cubic root of 126549721 is about 502.0578138523.

The spelling of 126549721 in words is "one hundred twenty-six million, five hundred forty-nine thousand, seven hundred twenty-one".