21311022806 has 4 divisors (see below), whose sum is σ = 31966534212. Its totient is φ = 10655511402.

The previous prime is 21311022791. The next prime is 21311022827. The reversal of 21311022806 is 60822011312.

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

It is a super-2 number, since 2×21311022806² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5327755700 + ... + 5327755703.

It is an arithmetic number, because the mean of its divisors is an integer number (7991633553).

Almost surely, 2^21311022806 is an apocalyptic number.

21311022806 is a deficient number, since it is larger than the sum of its proper divisors (10655511406).

21311022806 is a wasteful number, since it uses less digits than its factorization.

21311022806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10655511405.

The product of its (nonzero) digits is 1152, while the sum is 26.

The spelling of 21311022806 in words is "twenty-one billion, three hundred eleven million, twenty-two thousand, eight hundred six".