21865288256812 has 384 divisors, whose sum is σ = 54198750412800. Its totient is φ = 7598253600000.

The previous prime is 21865288256803. The next prime is 21865288256831.

21865288256812 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4567636683 + ... + 4567641469.

It is an arithmetic number, because the mean of its divisors is an integer number (141142579200).

Almost surely, 2^{21865288256812} is an apocalyptic number.

21865288256812 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 21865288256812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27099375206400).

21865288256812 is an abundant number, since it is smaller than the sum of its proper divisors (32333462155988).

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

21865288256812 is a wasteful number, since it uses less digits than its factorization.

21865288256812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5618 (or 5602 counting only the distinct ones).

The product of its digits is 58982400, while the sum is 64.

The spelling of 21865288256812 in words is "twenty-one trillion, eight hundred sixty-five billion, two hundred eighty-eight million, two hundred fifty-six thousand, eight hundred twelve".