21205422756672 has 2016 divisors, whose sum is σ = 81720744376320. Its totient is φ = 4783033221120.

The previous prime is 21205422756667. The next prime is 21205422756751. The reversal of 21205422756672 is 27665722450212.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 19948656813 + ... + 19948657875.

It is an arithmetic number, because the mean of its divisors is an integer number (40536083520).

Almost surely, 2^{21205422756672} is an apocalyptic number.

21205422756672 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 21205422756672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40860372188160).

21205422756672 is an abundant number, since it is smaller than the sum of its proper divisors (60515321619648).

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

21205422756672 is a wasteful number, since it uses less digits than its factorization.

21205422756672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189 (or 1155 counting only the distinct ones).

The product of its (nonzero) digits is 5644800, while the sum is 51.

The spelling of 21205422756672 in words is "twenty-one trillion, two hundred five billion, four hundred twenty-two million, seven hundred fifty-six thousand, six hundred seventy-two".