21298083840 has 768 divisors, whose sum is σ = 84913920000. Its totient is φ = 5019402240.

The previous prime is 21298083823. The next prime is 21298083841. The reversal of 21298083840 is 4838089212.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21298083841) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 142940086 + ... + 142940234.

It is an arithmetic number, because the mean of its divisors is an integer number (110565000).

Almost surely, 2^21298083840 is an apocalyptic number.

21298083840 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 21298083840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42456960000).

21298083840 is an abundant number, since it is smaller than the sum of its proper divisors (63615836160).

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

21298083840 is a wasteful number, since it uses less digits than its factorization.

21298083840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 21298083840 in words is "twenty-one billion, two hundred ninety-eight million, eighty-three thousand, eight hundred forty".