21630254 has 8 divisors (see below), whose sum is σ = 33057720. Its totient is φ = 10611016.

The previous prime is 21630251. The next prime is 21630269. The reversal of 21630254 is 45203612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21630251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101924 + ... + 102135.

It is an arithmetic number, because the mean of its divisors is an integer number (4132215).

Almost surely, 2^21630254 is an apocalyptic number.

21630254 is a deficient number, since it is larger than the sum of its proper divisors (11427466).

21630254 is a wasteful number, since it uses less digits than its factorization.

21630254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204114.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21630254 is about 4650.8336887057. The cubic root of 21630254 is about 278.6252940138.

Adding to 21630254 its reverse (45203612), we get a palindrome (66833866).

The spelling of 21630254 in words is "twenty-one million, six hundred thirty thousand, two hundred fifty-four".