21378226752 has 168 divisors, whose sum is σ = 64353216480. Its totient is φ = 6959312640.

The previous prime is 21378226741. The next prime is 21378226763. The reversal of 21378226752 is 25762287312.

21378226752 is a `hidden beast` number, since 2 + 1 + 378 + 226 + 7 + 52 = 666.

It is an interprime number because it is at equal distance from previous prime (21378226741) and next prime (21378226763).

It is a junction number, because it is equal to n+sod(n) for n = 21378226698 and 21378226707.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3191727 + ... + 3198417.

It is an arithmetic number, because the mean of its divisors is an integer number (383054860).

Almost surely, 2^21378226752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21378226752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32176608240).

21378226752 is an abundant number, since it is smaller than the sum of its proper divisors (42974989728).

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

21378226752 is an equidigital number, since it uses as much as digits as its factorization.

21378226752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6798 (or 6739 counting only the distinct ones).

The product of its digits is 564480, while the sum is 45.

The spelling of 21378226752 in words is "twenty-one billion, three hundred seventy-eight million, two hundred twenty-six thousand, seven hundred fifty-two".