21316400 has 120 divisors (see below), whose sum is σ = 61257984. Its totient is φ = 6969600.

The previous prime is 21316397. The next prime is 21316417. The reversal of 21316400 is 461312.

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, 64235 + ... + 64565.

Almost surely, 2^21316400 is an apocalyptic number.

21316400 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 21316400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30628992).

21316400 is an abundant number, since it is smaller than the sum of its proper divisors (39941584).

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

21316400 is a wasteful number, since it uses less digits than its factorization.

21316400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 368 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21316400 is about 4616.9687025147. The cubic root of 21316400 is about 277.2711095815.

Adding to 21316400 its reverse (461312), we get a palindrome (21777712).

It can be divided in two parts, 21316 and 400, that multiplied together give a square (8526400 = 2920²).

The spelling of 21316400 in words is "twenty-one million, three hundred sixteen thousand, four hundred".