21271299840 has 1080 divisors, whose sum is σ = 91351592640. Its totient is φ = 4709892096.

The previous prime is 21271299839. The next prime is 21271299859. The reversal of 21271299840 is 4899217212.

21271299840 is a `hidden beast` number, since 212 + 71 + 299 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1080).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 269256921 + ... + 269256999.

It is an arithmetic number, because the mean of its divisors is an integer number (84584808).

Almost surely, 2^21271299840 is an apocalyptic number.

21271299840 is a gapful number since it is divisible by the number (20) 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 21271299840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45675796320).

21271299840 is an abundant number, since it is smaller than the sum of its proper divisors (70080292800).

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

21271299840 is an equidigital number, since it uses as much as digits as its factorization.

21271299840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 21271299840 in words is "twenty-one billion, two hundred seventy-one million, two hundred ninety-nine thousand, eight hundred forty".