21423706 has 16 divisors (see below), whose sum is σ = 34214400. Its totient is φ = 10025920.

The previous prime is 21423679. The next prime is 21423709. The reversal of 21423706 is 60732412.

It is not an unprimeable number, because it can be changed into a prime (21423709) 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 7 ways as a sum of consecutive naturals, for example, 4845 + ... + 8143.

It is an arithmetic number, because the mean of its divisors is an integer number (2138400).

Almost surely, 2^21423706 is an apocalyptic number.

21423706 is a deficient number, since it is larger than the sum of its proper divisors (12790694).

21423706 is a wasteful number, since it uses less digits than its factorization.

21423706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3509.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21423706 is about 4628.5749426794. The cubic root of 21423706 is about 277.7355886978.

The spelling of 21423706 in words is "twenty-one million, four hundred twenty-three thousand, seven hundred six".