21443420400 has 60 divisors (see below), whose sum is σ = 68690427192. Its totient is φ = 5718245120.

The previous prime is 21443420371. The next prime is 21443420413. The reversal of 21443420400 is 402434412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×21443420400² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8933559 + ... + 8935958.

Almost surely, 2^21443420400 is an apocalyptic number.

21443420400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21443420400 is an abundant number, since it is smaller than the sum of its proper divisors (47247006792).

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

21443420400 is a wasteful number, since it uses less digits than its factorization.

21443420400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17869538 (or 17869527 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21443420400 its reverse (402434412), we get a palindrome (21845854812).

The spelling of 21443420400 in words is "twenty-one billion, four hundred forty-three million, four hundred twenty thousand, four hundred".