21044651 has 8 divisors (see below), whose sum is σ = 21615360. Its totient is φ = 20481192.

The previous prime is 21044627. The next prime is 21044687. The reversal of 21044651 is 15644012.

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

It is a cyclic number.

It is not a de Polignac number, because 21044651 - 2²² = 16850347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21044251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4346 + ... + 7808.

It is an arithmetic number, because the mean of its divisors is an integer number (2701920).

Almost surely, 2^21044651 is an apocalyptic number.

21044651 is a deficient number, since it is larger than the sum of its proper divisors (570709).

21044651 is a wasteful number, since it uses less digits than its factorization.

21044651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3625.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21044651 is about 4587.4449315496. Note that the first 3 decimals coincide. The cubic root of 21044651 is about 276.0878168712.

Adding to 21044651 its reverse (15644012), we get a palindrome (36688663).

The spelling of 21044651 in words is "twenty-one million, forty-four thousand, six hundred fifty-one".