21356172206 has 8 divisors (see below), whose sum is σ = 32200239504. Its totient is φ = 10622759040.

The previous prime is 21356172203. The next prime is 21356172223. The reversal of 21356172206 is 60227165312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21356172203) 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, 27663050 + ... + 27663821.

It is an arithmetic number, because the mean of its divisors is an integer number (4025029938).

Almost surely, 2^21356172206 is an apocalyptic number.

21356172206 is a deficient number, since it is larger than the sum of its proper divisors (10844067298).

21356172206 is a wasteful number, since it uses less digits than its factorization.

21356172206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55327066.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 21356172206 in words is "twenty-one billion, three hundred fifty-six million, one hundred seventy-two thousand, two hundred six".