126921 has 4 divisors (see below), whose sum is σ = 169232. Its totient is φ = 84612.

The previous prime is 126913. The next prime is 126923. The reversal of 126921 is 129621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 129621 = 3 ⋅43207.

It is not a de Polignac number, because 126921 - 2³ = 126913 is a prime.

It is a super-2 number, since 2×126921² = 32217880482, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126923) 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, 21151 + ... + 21156.

It is an arithmetic number, because the mean of its divisors is an integer number (42308).

2¹²⁶⁹²¹ is an apocalyptic number.

It is an amenable number.

126921 is a deficient number, since it is larger than the sum of its proper divisors (42311).

126921 is an equidigital number, since it uses as much as digits as its factorization.

126921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42310.

The product of its digits is 216, while the sum is 21.

The square root of 126921 is about 356.2597367090. The cubic root of 126921 is about 50.2548323364.

The spelling of 126921 in words is "one hundred twenty-six thousand, nine hundred twenty-one".