21003640513 has 16 divisors (see below), whose sum is σ = 21521111040. Its totient is φ = 20492170704.

The previous prime is 21003640501. The next prime is 21003640531. The reversal of 21003640513 is 31504630012.

It is a cyclic number.

It is not a de Polignac number, because 21003640513 - 2⁵ = 21003640481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21003640213) 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, 4388920 + ... + 4393702.

It is an arithmetic number, because the mean of its divisors is an integer number (1345069440).

Almost surely, 2^21003640513 is an apocalyptic number.

It is an amenable number.

21003640513 is a deficient number, since it is larger than the sum of its proper divisors (517470527).

21003640513 is a wasteful number, since it uses less digits than its factorization.

21003640513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5388.

The product of its (nonzero) digits is 2160, while the sum is 25.

The spelling of 21003640513 in words is "twenty-one billion, three million, six hundred forty thousand, five hundred thirteen".