21456742 has 8 divisors (see below), whose sum is σ = 32933736. Its totient is φ = 10478832.

The previous prime is 21456739. The next prime is 21456751. The reversal of 21456742 is 24765412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124663 + ... + 124834.

It is an arithmetic number, because the mean of its divisors is an integer number (4116717).

Almost surely, 2^21456742 is an apocalyptic number.

21456742 is a deficient number, since it is larger than the sum of its proper divisors (11476994).

21456742 is a wasteful number, since it uses less digits than its factorization.

21456742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249542.

The product of its digits is 13440, while the sum is 31.

The square root of 21456742 is about 4632.1422689723. The cubic root of 21456742 is about 277.8782742624.

The spelling of 21456742 in words is "twenty-one million, four hundred fifty-six thousand, seven hundred forty-two".