21424706 has 4 divisors (see below), whose sum is σ = 32137062. Its totient is φ = 10712352.

The previous prime is 21424699. The next prime is 21424759. The reversal of 21424706 is 60742412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19758025 + 1666681 = 4445^2 + 1291^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5356175 + ... + 5356178.

Almost surely, 2^21424706 is an apocalyptic number.

21424706 is a deficient number, since it is larger than the sum of its proper divisors (10712356).

21424706 is a wasteful number, since it uses less digits than its factorization.

21424706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10712355.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 21424706 is about 4628.6829660282. The cubic root of 21424706 is about 277.7399099431.

The spelling of 21424706 in words is "twenty-one million, four hundred twenty-four thousand, seven hundred six".