21512000 has 56 divisors (see below), whose sum is σ = 53294280. Its totient is φ = 8601600.

The previous prime is 21511999. The next prime is 21512017. The reversal of 21512000 is 21512.

It can be written as a sum of positive squares in 4 ways, for example, as 5125696 + 16386304 = 2264^2 + 4048^2 .

It is a super-2 number, since 2×21512000² = 925532288000000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6656 + ... + 9344.

Almost surely, 2^21512000 is an apocalyptic number.

21512000 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 21512000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26647140).

21512000 is an abundant number, since it is smaller than the sum of its proper divisors (31782280).

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

21512000 is an equidigital number, since it uses as much as digits as its factorization.

21512000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2716 (or 2696 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 21512000 is about 4638.1030605195. The cubic root of 21512000 is about 278.1166117068.

Adding to 21512000 its reverse (21512), we get a palindrome (21533512).

21512000 divided by its reverse (21512) gives a cube (1000 = 10³).

The spelling of 21512000 in words is "twenty-one million, five hundred twelve thousand".