21403642 has 16 divisors (see below), whose sum is σ = 34699392. Its totient is φ = 9843120.

The previous prime is 21403621. The next prime is 21403643. The reversal of 21403642 is 24630412.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21403643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6763 + ... + 9409.

It is an arithmetic number, because the mean of its divisors is an integer number (2168712).

Almost surely, 2^21403642 is an apocalyptic number.

21403642 is a deficient number, since it is larger than the sum of its proper divisors (13295750).

21403642 is a wasteful number, since it uses less digits than its factorization.

21403642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2973.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21403642 is about 4626.4070292182. The cubic root of 21403642 is about 277.6488588021.

The spelling of 21403642 in words is "twenty-one million, four hundred three thousand, six hundred forty-two".