21864206 has 24 divisors (see below), whose sum is σ = 40590864. Its totient is φ = 8648640.

The previous prime is 21864187. The next prime is 21864209. The reversal of 21864206 is 60246812.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21864209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2255 + ... + 6986.

It is an arithmetic number, because the mean of its divisors is an integer number (1691286).

Almost surely, 2^21864206 is an apocalyptic number.

21864206 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21864206 is a deficient number, since it is larger than the sum of its proper divisors (18726658).

21864206 is a wasteful number, since it uses less digits than its factorization.

21864206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9276 (or 9263 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21864206 is about 4675.9176639458. The cubic root of 21864206 is about 279.6262274628.

The spelling of 21864206 in words is "twenty-one million, eight hundred sixty-four thousand, two hundred six".