21140400 has 120 divisors (see below), whose sum is σ = 68884480. Its totient is φ = 5541120.

The previous prime is 21140389. The next prime is 21140423. The reversal of 21140400 is 404112.

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 (12).

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, 94689 + ... + 94911.

Almost surely, 2^21140400 is an apocalyptic number.

21140400 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 21140400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34442240).

21140400 is an abundant number, since it is smaller than the sum of its proper divisors (47744080).

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

21140400 is a wasteful number, since it uses less digits than its factorization.

21140400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21140400 is about 4597.8690716461. The cubic root of 21140400 is about 276.5058984361.

Adding to 21140400 its reverse (404112), we get a palindrome (21544512).

The spelling of 21140400 in words is "twenty-one million, one hundred forty thousand, four hundred".