21264212806 has 4 divisors (see below), whose sum is σ = 31896319212. Its totient is φ = 10632106402.

The previous prime is 21264212777. The next prime is 21264212807. The reversal of 21264212806 is 60821246212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21264212807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5316053200 + ... + 5316053203.

It is an arithmetic number, because the mean of its divisors is an integer number (7974079803).

Almost surely, 2^21264212806 is an apocalyptic number.

21264212806 is a deficient number, since it is larger than the sum of its proper divisors (10632106406).

21264212806 is a wasteful number, since it uses less digits than its factorization.

21264212806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10632106405.

The product of its (nonzero) digits is 18432, while the sum is 34.

The spelling of 21264212806 in words is "twenty-one billion, two hundred sixty-four million, two hundred twelve thousand, eight hundred six".