21216666666712 has 64 divisors (see below), whose sum is σ = 44816513955840. Its totient is φ = 9328915411200.

The previous prime is 21216666666709. The next prime is 21216666666721. The reversal of 21216666666712 is 21766666661212.

It is a hoax number, since the sum of its digits (58) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4848493 + ... + 8120419.

It is an arithmetic number, because the mean of its divisors is an integer number (700258030560).

Almost surely, 2^{21216666666712} is an apocalyptic number.

21216666666712 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21216666666712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22408256977920).

21216666666712 is an abundant number, since it is smaller than the sum of its proper divisors (23599847289128).

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

21216666666712 is a wasteful number, since it uses less digits than its factorization.

21216666666712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3274352 (or 3274348 counting only the distinct ones).

The product of its digits is 15676416, while the sum is 58.

The spelling of 21216666666712 in words is "twenty-one trillion, two hundred sixteen billion, six hundred sixty-six million, six hundred sixty-six thousand, seven hundred twelve".