21407642 has 8 divisors (see below), whose sum is σ = 33801600. Its totient is φ = 10140444.

The previous prime is 21407629. The next prime is 21407647. The reversal of 21407642 is 24670412.

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

It is not an unprimeable number, because it can be changed into a prime (21407647) 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 3 ways as a sum of consecutive naturals, for example, 281642 + ... + 281717.

It is an arithmetic number, because the mean of its divisors is an integer number (4225200).

Almost surely, 2^21407642 is an apocalyptic number.

21407642 is a deficient number, since it is larger than the sum of its proper divisors (12393958).

21407642 is a wasteful number, since it uses less digits than its factorization.

21407642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563380.

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

The square root of 21407642 is about 4626.8393099393. The cubic root of 21407642 is about 277.6661537755. Note that the first 3 decimals are identical.

The spelling of 21407642 in words is "twenty-one million, four hundred seven thousand, six hundred forty-two".