21787382 has 4 divisors (see below), whose sum is σ = 32681076. Its totient is φ = 10893690.

The previous prime is 21787379. The next prime is 21787393. The reversal of 21787382 is 28378712.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5446844 + ... + 5446847.

It is an arithmetic number, because the mean of its divisors is an integer number (8170269).

Almost surely, 2^21787382 is an apocalyptic number.

21787382 is a deficient number, since it is larger than the sum of its proper divisors (10893694).

21787382 is a wasteful number, since it uses less digits than its factorization.

21787382 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10893693.

The product of its digits is 37632, while the sum is 38.

The square root of 21787382 is about 4667.6955770487. The cubic root of 21787382 is about 279.2983366797.

The spelling of 21787382 in words is "twenty-one million, seven hundred eighty-seven thousand, three hundred eighty-two".