21264404406 has 192 divisors, whose sum is σ = 54832066560. Its totient is φ = 5372674560.

The previous prime is 21264404377. The next prime is 21264404437. The reversal of 21264404406 is 60440446212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 16470621 + ... + 16471911.

It is an arithmetic number, because the mean of its divisors is an integer number (285583680).

Almost surely, 2^21264404406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21264404406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27416033280).

21264404406 is an abundant number, since it is smaller than the sum of its proper divisors (33567662154).

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

21264404406 is a wasteful number, since it uses less digits than its factorization.

21264404406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1419 (or 1402 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 33.

The spelling of 21264404406 in words is "twenty-one billion, two hundred sixty-four million, four hundred four thousand, four hundred six".