21866513206 has 4 divisors (see below), whose sum is σ = 32799769812. Its totient is φ = 10933256602.

The previous prime is 21866513203. The next prime is 21866513219. The reversal of 21866513206 is 60231566812.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866513203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5466628300 + ... + 5466628303.

It is an arithmetic number, because the mean of its divisors is an integer number (8199942453).

Almost surely, 2^21866513206 is an apocalyptic number.

21866513206 is a deficient number, since it is larger than the sum of its proper divisors (10933256606).

21866513206 is a wasteful number, since it uses less digits than its factorization.

21866513206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10933256605.

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 21866513206 in words is "twenty-one billion, eight hundred sixty-six million, five hundred thirteen thousand, two hundred six".