21389242 has 8 divisors (see below), whose sum is σ = 36667296. Its totient is φ = 9166812.

The previous prime is 21389239. The next prime is 21389257. The reversal of 21389242 is 24298312.

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

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, 763888 + ... + 763915.

It is an arithmetic number, because the mean of its divisors is an integer number (4583412).

Almost surely, 2^21389242 is an apocalyptic number.

21389242 is a deficient number, since it is larger than the sum of its proper divisors (15278054).

21389242 is a wasteful number, since it uses less digits than its factorization.

21389242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1527812.

The product of its digits is 6912, while the sum is 31.

The square root of 21389242 is about 4624.8504840697. The cubic root of 21389242 is about 277.5865790503.

The spelling of 21389242 in words is "twenty-one million, three hundred eighty-nine thousand, two hundred forty-two".