21003550039 has 4 divisors (see below), whose sum is σ = 21004254040. Its totient is φ = 21002846040.

The previous prime is 21003550013. The next prime is 21003550081. The reversal of 21003550039 is 93005530012.

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 21003550039 - 2⁷ = 21003549911 is a prime.

It is a super-2 number, since 2×21003550039² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21003549989 and 21003550016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003551039) 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, 305172 + ... + 367609.

It is an arithmetic number, because the mean of its divisors is an integer number (5251063510).

Almost surely, 2^21003550039 is an apocalyptic number.

21003550039 is a deficient number, since it is larger than the sum of its proper divisors (704001).

21003550039 is an equidigital number, since it uses as much as digits as its factorization.

21003550039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704000.

The product of its (nonzero) digits is 4050, while the sum is 28.

The spelling of 21003550039 in words is "twenty-one billion, three million, five hundred fifty thousand, thirty-nine".