21513512003 has 4 divisors (see below), whose sum is σ = 21521060808. Its totient is φ = 21505963200.

The previous prime is 21513511997. The next prime is 21513512011. The reversal of 21513512003 is 30021531512.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21513512003 - 2¹⁰ = 21513510979 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21513512003.

It is not an unprimeable number, because it can be changed into a prime (21513512303) 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, 3770126 + ... + 3775827.

It is an arithmetic number, because the mean of its divisors is an integer number (5380265202).

Almost surely, 2^21513512003 is an apocalyptic number.

21513512003 is a deficient number, since it is larger than the sum of its proper divisors (7548805).

21513512003 is an equidigital number, since it uses as much as digits as its factorization.

21513512003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7548804.

The product of its (nonzero) digits is 900, while the sum is 23.

The spelling of 21513512003 in words is "twenty-one billion, five hundred thirteen million, five hundred twelve thousand, three".