21440651 has 8 divisors (see below), whose sum is σ = 21835008. Its totient is φ = 21049000.

The previous prime is 21440647. The next prime is 21440677. The reversal of 21440651 is 15604412.

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 21440651 - 2² = 21440647 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21440681) 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 7 ways as a sum of consecutive naturals, for example, 21596 + ... + 22566.

It is an arithmetic number, because the mean of its divisors is an integer number (2729376).

Almost surely, 2^21440651 is an apocalyptic number.

21440651 is a deficient number, since it is larger than the sum of its proper divisors (394357).

21440651 is an equidigital number, since it uses as much as digits as its factorization.

21440651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353.

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

The square root of 21440651 is about 4630.4050578756. The cubic root of 21440651 is about 277.8087940418.

The spelling of 21440651 in words is "twenty-one million, four hundred forty thousand, six hundred fifty-one".