21810806712 has 128 divisors (see below), whose sum is σ = 63463910400. Its totient is φ = 6927313536.

The previous prime is 21810806683. The next prime is 21810806737. The reversal of 21810806712 is 21760801812.

It is a super-2 number, since 2×21810806712² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 in 31 ways as a sum of consecutive naturals, for example, 1298238 + ... + 1314930.

It is an arithmetic number, because the mean of its divisors is an integer number (495811800).

Almost surely, 2^21810806712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21810806712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31731955200).

21810806712 is an abundant number, since it is smaller than the sum of its proper divisors (41653103688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21810806712 is a wasteful number, since it uses less digits than its factorization.

21810806712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16994 (or 16984 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The spelling of 21810806712 in words is "twenty-one billion, eight hundred ten million, eight hundred six thousand, seven hundred twelve".