21423210400440 has 384 divisors, whose sum is σ = 74511549665280. Its totient is φ = 5328733132800.

The previous prime is 21423210400433. The next prime is 21423210400469. The reversal of 21423210400440 is 4400401232412.

21423210400440 is a `hidden beast` number, since 2 + 1 + 4 + 2 + 3 + 210 + 4 + 0 + 0 + 440 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 37695429 + ... + 38259531.

It is an arithmetic number, because the mean of its divisors is an integer number (194040493920).

Almost surely, 2^{21423210400440} is an apocalyptic number.

21423210400440 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 21423210400440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37255774832640).

21423210400440 is an abundant number, since it is smaller than the sum of its proper divisors (53088339264840).

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

21423210400440 is a wasteful number, since it uses less digits than its factorization.

21423210400440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564275 (or 564268 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 27.

Adding to 21423210400440 its reverse (4400401232412), we get a palindrome (25823611632852).

The spelling of 21423210400440 in words is "twenty-one trillion, four hundred twenty-three billion, two hundred ten million, four hundred thousand, four hundred forty".