21082400 has 108 divisors (see below), whose sum is σ = 55062882. Its totient is φ = 7879680.

The previous prime is 21082361. The next prime is 21082403. The reversal of 21082400 is 428012.

It can be written as a sum of positive squares in 3 ways, for example, as 16224784 + 4857616 = 4028^2 + 2204^2 .

It is not an unprimeable number, because it can be changed into a prime (21082403) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 288764 + ... + 288836.

Almost surely, 2^21082400 is an apocalyptic number.

21082400 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 21082400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27531441).

21082400 is an abundant number, since it is smaller than the sum of its proper divisors (33980482).

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

21082400 is a wasteful number, since it uses less digits than its factorization.

21082400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 21082400 is about 4591.5574699659. The cubic root of 21082400 is about 276.2527964610.

The spelling of 21082400 in words is "twenty-one million, eighty-two thousand, four hundred".