21393442 has 8 divisors (see below), whose sum is σ = 36674496. Its totient is φ = 9168612.

The previous prime is 21393433. The next prime is 21393457. The reversal of 21393442 is 24439312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21393442.

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, 764038 + ... + 764065.

It is an arithmetic number, because the mean of its divisors is an integer number (4584312).

Almost surely, 2^21393442 is an apocalyptic number.

21393442 is a deficient number, since it is larger than the sum of its proper divisors (15281054).

21393442 is a wasteful number, since it uses less digits than its factorization.

21393442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528112.

The product of its digits is 5184, while the sum is 28.

The square root of 21393442 is about 4625.3045305147. The cubic root of 21393442 is about 277.6047468647.

It can be divided in two parts, 2139344 and 2, that added together give a triangular number (2139346 = T₂₀₆₈).

The spelling of 21393442 in words is "twenty-one million, three hundred ninety-three thousand, four hundred forty-two".