21001440013 has 4 divisors (see below), whose sum is σ = 21004239168. Its totient is φ = 20998640860.

The previous prime is 21001439989. The next prime is 21001440067. The reversal of 21001440013 is 31004410012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21001440013 - 2¹⁷ = 21001308941 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 (21001440113) 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, 1388293 + ... + 1403338.

It is an arithmetic number, because the mean of its divisors is an integer number (5251059792).

Almost surely, 2^21001440013 is an apocalyptic number.

It is an amenable number.

21001440013 is a deficient number, since it is larger than the sum of its proper divisors (2799155).

21001440013 is an equidigital number, since it uses as much as digits as its factorization.

21001440013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2799154.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21001440013 its reverse (31004410012), we get a palindrome (52005850025).

The spelling of 21001440013 in words is "twenty-one billion, one million, four hundred forty thousand, thirteen".