21023630 has 16 divisors (see below), whose sum is σ = 38072160. Its totient is φ = 8358432.

The previous prime is 21023623. The next prime is 21023641. The reversal of 21023630 is 3632012.

It is a super-4 number, since 4×21023630⁴ (a number of 30 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21023599 and 21023608.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 4625 + ... + 7964.

It is an arithmetic number, because the mean of its divisors is an integer number (2379510).

Almost surely, 2^21023630 is an apocalyptic number.

21023630 is a deficient number, since it is larger than the sum of its proper divisors (17048530).

21023630 is a wasteful number, since it uses less digits than its factorization.

21023630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12763.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 21023630 is about 4585.1532144521. The cubic root of 21023630 is about 275.9958604014.

Adding to 21023630 its reverse (3632012), we get a palindrome (24655642).

The spelling of 21023630 in words is "twenty-one million, twenty-three thousand, six hundred thirty".