21266642012 has 144 divisors (see below), whose sum is σ = 49714506240. Its totient is φ = 7769520000.

The previous prime is 21266642011. The next prime is 21266642021. The reversal of 21266642012 is 21024666212.

It is a self number, because there is not a number n which added to its sum of digits gives 21266642012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266642011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6499937 + ... + 6503207.

Almost surely, 2^21266642012 is an apocalyptic number.

21266642012 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 21266642012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24857253120).

21266642012 is an abundant number, since it is smaller than the sum of its proper divisors (28447864228).

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

21266642012 is a wasteful number, since it uses less digits than its factorization.

21266642012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3424 (or 3411 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The spelling of 21266642012 in words is "twenty-one billion, two hundred sixty-six million, six hundred forty-two thousand, twelve".