21003243015 has 16 divisors (see below), whose sum is σ = 33696764928. Its totient is φ = 11171204256.

The previous prime is 21003243007. The next prime is 21003243031. The reversal of 21003243015 is 51034230012.

It is not a de Polignac number, because 21003243015 - 2³ = 21003243007 is a prime.

It is a super-2 number, since 2×21003243015² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21003242982 and 21003243000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1902147 + ... + 1913156.

It is an arithmetic number, because the mean of its divisors is an integer number (2106047808).

Almost surely, 2^21003243015 is an apocalyptic number.

21003243015 is a deficient number, since it is larger than the sum of its proper divisors (12693521913).

21003243015 is a wasteful number, since it uses less digits than its factorization.

21003243015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3815678.

The product of its (nonzero) digits is 720, while the sum is 21.

Adding to 21003243015 its reverse (51034230012), we get a palindrome (72037473027).

The spelling of 21003243015 in words is "twenty-one billion, three million, two hundred forty-three thousand, fifteen".