21816201 has 8 divisors (see below), whose sum is σ = 31732704. Its totient is φ = 13221920.

The previous prime is 21816191. The next prime is 21816209. The reversal of 21816201 is 10261812.

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 21816201 - 2¹⁰ = 21815177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21816209) 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, 330516 + ... + 330581.

It is an arithmetic number, because the mean of its divisors is an integer number (3966588).

Almost surely, 2^21816201 is an apocalyptic number.

It is an amenable number.

21816201 is a deficient number, since it is larger than the sum of its proper divisors (9916503).

21816201 is a wasteful number, since it uses less digits than its factorization.

21816201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661111.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21816201 is about 4670.7816262377. The cubic root of 21816201 is about 279.4214286054.

The spelling of 21816201 in words is "twenty-one million, eight hundred sixteen thousand, two hundred one".