21451360 has 96 divisors (see below), whose sum is σ = 58786560. Its totient is φ = 7245312.

The previous prime is 21451357. The next prime is 21451363. The reversal of 21451360 is 6315412.

It is an interprime number because it is at equal distance from previous prime (21451357) and next prime (21451363).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451363) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119751 + ... + 119929.

It is an arithmetic number, because the mean of its divisors is an integer number (612360).

Almost surely, 2^21451360 is an apocalyptic number.

21451360 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 21451360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29393280).

21451360 is an abundant number, since it is smaller than the sum of its proper divisors (37335200).

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

21451360 is a wasteful number, since it uses less digits than its factorization.

21451360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 300 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21451360 is about 4631.5612918324. The cubic root of 21451360 is about 277.8550388938.

Adding to 21451360 its reverse (6315412), we get a palindrome (27766772).

The spelling of 21451360 in words is "twenty-one million, four hundred fifty-one thousand, three hundred sixty".