21368261376 has 504 divisors, whose sum is σ = 79783893504. Its totient is φ = 5546465280.

The previous prime is 21368261363. The next prime is 21368261381. The reversal of 21368261376 is 67316286312.

21368261376 is a `hidden beast` number, since 2 + 13 + 6 + 8 + 261 + 376 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 14369305 + ... + 14370791.

It is an arithmetic number, because the mean of its divisors is an integer number (158301376).

Almost surely, 2^21368261376 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 21368261376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39891946752).

21368261376 is an abundant number, since it is smaller than the sum of its proper divisors (58415632128).

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

21368261376 is an equidigital number, since it uses as much as digits as its factorization.

21368261376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1539 (or 1510 counting only the distinct ones).

The product of its digits is 435456, while the sum is 45.

The spelling of 21368261376 in words is "twenty-one billion, three hundred sixty-eight million, two hundred sixty-one thousand, three hundred seventy-six".