21444032400 has 120 divisors (see below), whose sum is σ = 78505612224. Its totient is φ = 4901491200.

The previous prime is 21444032383. The next prime is 21444032413. The reversal of 21444032400 is 423044412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1268031 + ... + 1284830.

Almost surely, 2^21444032400 is an apocalyptic number.

21444032400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21444032400 is an abundant number, since it is smaller than the sum of its proper divisors (57061579824).

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

21444032400 is a wasteful number, since it uses less digits than its factorization.

21444032400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2552889 (or 2552878 counting only the distinct ones).

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

Adding to 21444032400 its reverse (423044412), we get a palindrome (21867076812).

The spelling of 21444032400 in words is "twenty-one billion, four hundred forty-four million, thirty-two thousand, four hundred".