21265400206 has 16 divisors (see below), whose sum is σ = 32203391616. Its totient is φ = 10530980856.

The previous prime is 21265400161. The next prime is 21265400327. The reversal of 21265400206 is 60200456212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1328905 + ... + 1344811.

It is an arithmetic number, because the mean of its divisors is an integer number (2012711976).

Almost surely, 2^21265400206 is an apocalyptic number.

21265400206 is a deficient number, since it is larger than the sum of its proper divisors (10937991410).

21265400206 is a wasteful number, since it uses less digits than its factorization.

21265400206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22263.

The product of its (nonzero) digits is 5760, while the sum is 28.

Adding to 21265400206 its reverse (60200456212), we get a palindrome (81465856418).

The spelling of 21265400206 in words is "twenty-one billion, two hundred sixty-five million, four hundred thousand, two hundred six".