21120433400 has 96 divisors (see below), whose sum is σ = 53745310080. Its totient is φ = 7654896000.

The previous prime is 21120433391. The next prime is 21120433409. The reversal of 21120433400 is 433402112.

It is an interprime number because it is at equal distance from previous prime (21120433391) and next prime (21120433409).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120433409) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 659765 + ... + 691035.

It is an arithmetic number, because the mean of its divisors is an integer number (559846980).

Almost surely, 2^21120433400 is an apocalyptic number.

21120433400 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 21120433400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26872655040).

21120433400 is an abundant number, since it is smaller than the sum of its proper divisors (32624876680).

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

21120433400 is a wasteful number, since it uses less digits than its factorization.

21120433400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31605 (or 31596 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21120433400 its reverse (433402112), we get a palindrome (21553835512).

The spelling of 21120433400 in words is "twenty-one billion, one hundred twenty million, four hundred thirty-three thousand, four hundred".