126643921 has 4 divisors (see below), whose sum is σ = 126744372. Its totient is φ = 126543472.

The previous prime is 126643919. The next prime is 126643963. The reversal of 126643921 is 129346621.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129346621 = 79 ⋅1637299.

It can be written as a sum of positive squares in 2 ways, for example, as 45373696 + 81270225 = 6736^2 + 9015^2 .

It is a cyclic number.

It is not a de Polignac number, because 126643921 - 2¹ = 126643919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126646921) 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, 48310 + ... + 50863.

It is an arithmetic number, because the mean of its divisors is an integer number (31686093).

Almost surely, 2^126643921 is an apocalyptic number.

It is an amenable number.

126643921 is a deficient number, since it is larger than the sum of its proper divisors (100451).

126643921 is an equidigital number, since it uses as much as digits as its factorization.

126643921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100450.

The product of its digits is 15552, while the sum is 34.

The square root of 126643921 is about 11253.6181292951. The cubic root of 126643921 is about 502.1823554575.

The spelling of 126643921 in words is "one hundred twenty-six million, six hundred forty-three thousand, nine hundred twenty-one".