21400000 has 84 divisors (see below), whose sum is σ = 53574696. Its totient is φ = 8480000.

The previous prime is 21399979. The next prime is 21400003. The reversal of 21400000 is 412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 199947 + ... + 200053.

It is an arithmetic number, because the mean of its divisors is an integer number (637794).

Almost surely, 2^21400000 is an apocalyptic number.

21400000 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 21400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26787348).

21400000 is an abundant number, since it is smaller than the sum of its proper divisors (32174696).

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

21400000 is an frugal number, since it uses more digits than its factorization.

21400000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 21400000 is about 4626.0134024882. The cubic root of 21400000 is about 277.6331098546.

Adding to 21400000 its reverse (412), we get a palindrome (21400412).

The spelling of 21400000 in words is "twenty-one million, four hundred thousand".