21666372213 has 16 divisors (see below), whose sum is σ = 29161774400. Its totient is φ = 14307684480.

The previous prime is 21666372157. The next prime is 21666372257. The reversal of 21666372213 is 31227366612.

It is not a de Polignac number, because 21666372213 - 2¹² = 21666368117 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 (21666372293) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1539378 + ... + 1553388.

It is an arithmetic number, because the mean of its divisors is an integer number (1822610900).

Almost surely, 2^21666372213 is an apocalyptic number.

It is an amenable number.

21666372213 is a deficient number, since it is larger than the sum of its proper divisors (7495402187).

21666372213 is a wasteful number, since it uses less digits than its factorization.

21666372213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18852.

The product of its digits is 108864, while the sum is 39.

The spelling of 21666372213 in words is "twenty-one billion, six hundred sixty-six million, three hundred seventy-two thousand, two hundred thirteen".