21306258206 has 4 divisors (see below), whose sum is σ = 31959387312. Its totient is φ = 10653129102.

The previous prime is 21306258203. The next prime is 21306258313. The reversal of 21306258206 is 60285260312.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21306258203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5326564550 + ... + 5326564553.

It is an arithmetic number, because the mean of its divisors is an integer number (7989846828).

Almost surely, 2^21306258206 is an apocalyptic number.

21306258206 is a deficient number, since it is larger than the sum of its proper divisors (10653129106).

21306258206 is a wasteful number, since it uses less digits than its factorization.

21306258206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10653129105.

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 21306258206 in words is "twenty-one billion, three hundred six million, two hundred fifty-eight thousand, two hundred six".