21863887 has 8 divisors (see below), whose sum is σ = 23238576. Its totient is φ = 20499072.

The previous prime is 21863879. The next prime is 21863893. The reversal of 21863887 is 78836812.

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 21863887 - 2³ = 21863879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21863827) 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, 2388 + ... + 7030.

It is an arithmetic number, because the mean of its divisors is an integer number (2904822).

Almost surely, 2^21863887 is an apocalyptic number.

21863887 is a deficient number, since it is larger than the sum of its proper divisors (1374689).

21863887 is a wasteful number, since it uses less digits than its factorization.

21863887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4937.

The product of its digits is 129024, while the sum is 43.

The square root of 21863887 is about 4675.8835528700. The cubic root of 21863887 is about 279.6248675354.

The spelling of 21863887 in words is "twenty-one million, eight hundred sixty-three thousand, eight hundred eighty-seven".