21863387 has 8 divisors (see below), whose sum is σ = 26908896. Its totient is φ = 17298432.

The previous prime is 21863383. The next prime is 21863407. The reversal of 21863387 is 78336812.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21863387 - 2² = 21863383 is a prime.

It is a super-2 number, since 2×21863387² = 956015382223538, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21863387.

It is not an unprimeable number, because it can be changed into a prime (21863381) 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, 120038 + ... + 120219.

It is an arithmetic number, because the mean of its divisors is an integer number (3363612).

Almost surely, 2^21863387 is an apocalyptic number.

21863387 is a deficient number, since it is larger than the sum of its proper divisors (5045509).

21863387 is a wasteful number, since it uses less digits than its factorization.

21863387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240277.

The product of its digits is 48384, while the sum is 38.

The square root of 21863387 is about 4675.8300867333. The cubic root of 21863387 is about 279.6227359611.

The spelling of 21863387 in words is "twenty-one million, eight hundred sixty-three thousand, three hundred eighty-seven".