21282976638 has 288 divisors, whose sum is σ = 61307850240. Its totient is φ = 5471504640.

The previous prime is 21282976621. The next prime is 21282976639. The reversal of 21282976638 is 83667928212.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21282976639) 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 143 ways as a sum of consecutive naturals, for example, 29600443 + ... + 29601161.

It is an arithmetic number, because the mean of its divisors is an integer number (212874480).

Almost surely, 2^21282976638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21282976638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30653925120).

21282976638 is an abundant number, since it is smaller than the sum of its proper divisors (40024873602).

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

21282976638 is a wasteful number, since it uses less digits than its factorization.

21282976638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874 (or 855 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 54.

The spelling of 21282976638 in words is "twenty-one billion, two hundred eighty-two million, nine hundred seventy-six thousand, six hundred thirty-eight".