126161721 has 36 divisors (see below), whose sum is σ = 212779632. Its totient is φ = 71823024.

The previous prime is 126161719. The next prime is 126161747. The reversal of 126161721 is 127161621.

It is a happy number.

126161721 is a `hidden beast` number, since 1 + 26 + 1 + 617 + 21 = 666.

It is not a de Polignac number, because 126161721 - 2¹ = 126161719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (126161621) 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 35 ways as a sum of consecutive naturals, for example, 230370 + ... + 230916.

Almost surely, 2^126161721 is an apocalyptic number.

It is an amenable number.

126161721 is a deficient number, since it is larger than the sum of its proper divisors (86617911).

126161721 is a wasteful number, since it uses less digits than its factorization.

126161721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1090 (or 1080 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 126161721 is about 11232.1734762244. The cubic root of 126161721 is about 501.5441873944.

The spelling of 126161721 in words is "one hundred twenty-six million, one hundred sixty-one thousand, seven hundred twenty-one".