21630000 has 200 divisors, whose sum is σ = 80574208. Its totient is φ = 4896000.

The previous prime is 21629977. The next prime is 21630013. The reversal of 21630000 is 3612.

It is a tau number, because it is divible by the number of its divisors (200).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 209949 + ... + 210051.

Almost surely, 2^21630000 is an apocalyptic number.

21630000 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 21630000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40287104).

21630000 is an abundant number, since it is smaller than the sum of its proper divisors (58944208).

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

21630000 is a wasteful number, since it uses less digits than its factorization.

21630000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21630000 is about 4650.8063816934. The cubic root of 21630000 is about 278.6242033947.

Adding to 21630000 its reverse (3612), we get a palindrome (21633612).

The spelling of 21630000 in words is "twenty-one million, six hundred thirty thousand".