21630160 has 40 divisors (see below), whose sum is σ = 50807016. Its totient is φ = 8563200.

The previous prime is 21630131. The next prime is 21630179. The reversal of 21630160 is 6103612.

It can be written as a sum of positive squares in 4 ways, for example, as 1774224 + 19855936 = 1332^2 + 4456^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-4 number, since 4×21630160⁴ (a number of 30 digits) contains 4444 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, 6742 + ... + 9418.

Almost surely, 2^21630160 is an apocalyptic number.

21630160 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 21630160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25403508).

21630160 is an abundant number, since it is smaller than the sum of its proper divisors (29176856).

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

21630160 is a wasteful number, since it uses less digits than its factorization.

21630160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2791 (or 2785 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 21630160 is about 4650.8235829797. The cubic root of 21630160 is about 278.6248903998.

Adding to 21630160 its reverse (6103612), we get a palindrome (27733772).

The spelling of 21630160 in words is "twenty-one million, six hundred thirty thousand, one hundred sixty".