21221178688512 has 880 divisors, whose sum is σ = 73612259360640. Its totient is φ = 6018151219200.

The previous prime is 21221178688511. The next prime is 21221178688531. The reversal of 21221178688512 is 21588687112212.

21221178688512 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 117 + 8 + 6 + 8 + 8 + 512 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (21221178688511) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2807401789 + ... + 2807409347.

It is an arithmetic number, because the mean of its divisors is an integer number (83650294728).

Almost surely, 2^{21221178688512} is an apocalyptic number.

21221178688512 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 21221178688512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36806129680320).

21221178688512 is an abundant number, since it is smaller than the sum of its proper divisors (52391080672128).

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

21221178688512 is a wasteful number, since it uses less digits than its factorization.

21221178688512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7800 (or 7773 counting only the distinct ones).

The product of its digits is 1720320, while the sum is 54.

The spelling of 21221178688512 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred seventy-eight million, six hundred eighty-eight thousand, five hundred twelve".