21396742 has 8 divisors (see below), whose sum is σ = 32187096. Its totient is φ = 10667712.

The previous prime is 21396733. The next prime is 21396743. The reversal of 21396742 is 24769312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21396698 and 21396707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21396743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14448 + ... + 15859.

It is an arithmetic number, because the mean of its divisors is an integer number (4023387).

Almost surely, 2^21396742 is an apocalyptic number.

21396742 is a deficient number, since it is larger than the sum of its proper divisors (10790354).

21396742 is a wasteful number, since it uses less digits than its factorization.

21396742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30662.

The product of its digits is 18144, while the sum is 34.

The square root of 21396742 is about 4625.6612500269. The cubic root of 21396742 is about 277.6190199079.

The spelling of 21396742 in words is "twenty-one million, three hundred ninety-six thousand, seven hundred forty-two".