126337721 has 4 divisors (see below), whose sum is σ = 129752292. Its totient is φ = 122923152.

The previous prime is 126337699. The next prime is 126337723. The reversal of 126337721 is 127733621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127733621 = 1039 ⋅122939.

It can be written as a sum of positive squares in 2 ways, for example, as 113124496 + 13213225 = 10636^2 + 3635^2 .

It is a cyclic number.

It is not a de Polignac number, because 126337721 - 2⁶ = 126337657 is a prime.

It is a super-2 number, since 2×126337721² = 31922439494947682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126337723) 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, 1707230 + ... + 1707303.

It is an arithmetic number, because the mean of its divisors is an integer number (32438073).

Almost surely, 2^126337721 is an apocalyptic number.

It is an amenable number.

126337721 is a deficient number, since it is larger than the sum of its proper divisors (3414571).

126337721 is an equidigital number, since it uses as much as digits as its factorization.

126337721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3414570.

The product of its digits is 10584, while the sum is 32.

The square root of 126337721 is about 11240.0053825610. The cubic root of 126337721 is about 501.7773029032. Note that the first 3 decimals are identical.

The spelling of 126337721 in words is "one hundred twenty-six million, three hundred thirty-seven thousand, seven hundred twenty-one".