21446389440 has 840 divisors, whose sum is σ = 92843725920. Its totient is φ = 4602396672.

The previous prime is 21446389427. The next prime is 21446389451. The reversal of 21446389440 is 4498364412.

21446389440 is a `hidden beast` number, since 2 + 1 + 4 + 4 + 638 + 9 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (840).

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

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 52435956 + ... + 52436364.

Almost surely, 2^21446389440 is an apocalyptic number.

21446389440 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 21446389440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46421862960).

21446389440 is an abundant number, since it is smaller than the sum of its proper divisors (71397336480).

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

21446389440 is a wasteful number, since it uses less digits than its factorization.

21446389440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479 (or 443 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 45.

The spelling of 21446389440 in words is "twenty-one billion, four hundred forty-six million, three hundred eighty-nine thousand, four hundred forty".