21208449024 has 360 divisors, whose sum is σ = 72708138048. Its totient is φ = 6051594240.

The previous prime is 21208449019. The next prime is 21208449029. The reversal of 21208449024 is 42094480212.

21208449024 is a `hidden beast` number, since 2 + 1 + 208 + 449 + 0 + 2 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21208449019) and next prime (21208449029).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21208449024.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21208449029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27868804 + ... + 27869564.

Almost surely, 2^21208449024 is an apocalyptic number.

21208449024 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 21208449024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36354069024).

21208449024 is an abundant number, since it is smaller than the sum of its proper divisors (51499689024).

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

21208449024 is an frugal number, since it uses more digits than its factorization.

21208449024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811 (or 773 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The spelling of 21208449024 in words is "twenty-one billion, two hundred eight million, four hundred forty-nine thousand, twenty-four".