21191847264 has 288 divisors, whose sum is σ = 71653510656. Its totient is φ = 6035420160.

The previous prime is 21191847139. The next prime is 21191847289. The reversal of 21191847264 is 46274819112.

21191847264 is a `hidden beast` number, since 2 + 119 + 1 + 8 + 472 + 64 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33584229 + ... + 33584859.

It is an arithmetic number, because the mean of its divisors is an integer number (248796912).

Almost surely, 2^21191847264 is an apocalyptic number.

21191847264 is a gapful number since it is divisible by the number (24) 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 21191847264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35826755328).

21191847264 is an abundant number, since it is smaller than the sum of its proper divisors (50461663392).

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

21191847264 is an equidigital number, since it uses as much as digits as its factorization.

21191847264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280 (or 1260 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The spelling of 21191847264 in words is "twenty-one billion, one hundred ninety-one million, eight hundred forty-seven thousand, two hundred sixty-four".