21380387 has 8 divisors (see below), whose sum is σ = 24677472. Its totient is φ = 18144000.

The previous prime is 21380371. The next prime is 21380399. The reversal of 21380387 is 78308312.

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

It is not a de Polignac number, because 21380387 - 2⁴ = 21380371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21380687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14414 + ... + 15827.

It is an arithmetic number, because the mean of its divisors is an integer number (3084684).

Almost surely, 2^21380387 is an apocalyptic number.

21380387 is a deficient number, since it is larger than the sum of its proper divisors (3297085).

21380387 is a wasteful number, since it uses less digits than its factorization.

21380387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30349.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21380387 is about 4623.8930567218. The cubic root of 21380387 is about 277.5482674474.

Adding to 21380387 its reverse (78308312), we get a palindrome (99688699).

The spelling of 21380387 in words is "twenty-one million, three hundred eighty thousand, three hundred eighty-seven".