21396450240 has 1344 divisors, whose sum is σ = 94322188800. Its totient is φ = 4512153600.

The previous prime is 21396450233. The next prime is 21396450293. The reversal of 21396450240 is 4205469312.

It is a happy number.

21396450240 is a `hidden beast` number, since 2 + 1 + 3 + 9 + 645 + 0 + 2 + 4 + 0 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21396450195 and 21396450204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 521864620 + ... + 521864660.

It is an arithmetic number, because the mean of its divisors is an integer number (70180200).

Almost surely, 2^21396450240 is an apocalyptic number.

21396450240 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 21396450240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47161094400).

21396450240 is an abundant number, since it is smaller than the sum of its proper divisors (72925738560).

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

21396450240 is a wasteful number, since it uses less digits than its factorization.

21396450240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21396450240 in words is "twenty-one billion, three hundred ninety-six million, four hundred fifty thousand, two hundred forty".