21230651 has 4 divisors (see below), whose sum is σ = 22863792. Its totient is φ = 19597512.

The previous prime is 21230641. The next prime is 21230689. The reversal of 21230651 is 15603212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21230651 - 2¹⁴ = 21214267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21230611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 816551 + ... + 816576.

It is an arithmetic number, because the mean of its divisors is an integer number (5715948).

Almost surely, 2^21230651 is an apocalyptic number.

21230651 is a deficient number, since it is larger than the sum of its proper divisors (1633141).

21230651 is a wasteful number, since it uses less digits than its factorization.

21230651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1633140.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21230651 is about 4607.6730569779. The cubic root of 21230651 is about 276.8988191932.

Adding to 21230651 its reverse (15603212), we get a palindrome (36833863).

The spelling of 21230651 in words is "twenty-one million, two hundred thirty thousand, six hundred fifty-one".