21044320151 has 4 divisors (see below), whose sum is σ = 21044869272. Its totient is φ = 21043771032.

The previous prime is 21044320109. The next prime is 21044320153. The reversal of 21044320151 is 15102344012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21044320151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044320153) 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, 212381 + ... + 295286.

It is an arithmetic number, because the mean of its divisors is an integer number (5261217318).

Almost surely, 2^21044320151 is an apocalyptic number.

21044320151 is a deficient number, since it is larger than the sum of its proper divisors (549121).

21044320151 is an equidigital number, since it uses as much as digits as its factorization.

21044320151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549120.

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

Adding to 21044320151 its reverse (15102344012), we get a palindrome (36146664163).

The spelling of 21044320151 in words is "twenty-one billion, forty-four million, three hundred twenty thousand, one hundred fifty-one".