21864001 has 4 divisors (see below), whose sum is σ = 21873600. Its totient is φ = 21854404.

The previous prime is 21863993. The next prime is 21864013. The reversal of 21864001 is 10046812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21864001 - 2³ = 21863993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21864061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 780 + ... + 6658.

It is an arithmetic number, because the mean of its divisors is an integer number (5468400).

Almost surely, 2^21864001 is an apocalyptic number.

It is an amenable number.

21864001 is a deficient number, since it is larger than the sum of its proper divisors (9599).

21864001 is an equidigital number, since it uses as much as digits as its factorization.

21864001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9598.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21864001 is about 4675.8957430636. The cubic root of 21864001 is about 279.6253535298.

The spelling of 21864001 in words is "twenty-one million, eight hundred sixty-four thousand, one".