21001323847 has 16 divisors (see below), whose sum is σ = 25496190720. Its totient is φ = 16887028608.

The previous prime is 21001323841. The next prime is 21001323853. The reversal of 21001323847 is 74832310012.

It is an interprime number because it is at equal distance from previous prime (21001323841) and next prime (21001323853).

It is not a de Polignac number, because 21001323847 - 2¹¹ = 21001321799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001323841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 250897 + ... + 323962.

It is an arithmetic number, because the mean of its divisors is an integer number (1593511920).

Almost surely, 2^21001323847 is an apocalyptic number.

21001323847 is a deficient number, since it is larger than the sum of its proper divisors (4494866873).

21001323847 is a wasteful number, since it uses less digits than its factorization.

21001323847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575190.

The product of its (nonzero) digits is 8064, while the sum is 31.

Adding to 21001323847 its reverse (74832310012), we get a palindrome (95833633859).

The spelling of 21001323847 in words is "twenty-one billion, one million, three hundred twenty-three thousand, eight hundred forty-seven".