21382642 has 4 divisors (see below), whose sum is σ = 32073966. Its totient is φ = 10691320.

The previous prime is 21382597. The next prime is 21382661. The reversal of 21382642 is 24628312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20894041 + 488601 = 4571^2 + 699^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21382642.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5345659 + ... + 5345662.

Almost surely, 2^21382642 is an apocalyptic number.

21382642 is a deficient number, since it is larger than the sum of its proper divisors (10691324).

21382642 is a wasteful number, since it uses less digits than its factorization.

21382642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10691323.

The product of its digits is 4608, while the sum is 28.

The square root of 21382642 is about 4624.1368924373. The cubic root of 21382642 is about 277.5580248221.

The spelling of 21382642 in words is "twenty-one million, three hundred eighty-two thousand, six hundred forty-two".