21004550439 has 4 divisors (see below), whose sum is σ = 28006067256. Its totient is φ = 14003033624.

The previous prime is 21004550377. The next prime is 21004550467. The reversal of 21004550439 is 93405540012.

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 21004550439 - 2¹⁹ = 21004026151 is a prime.

It is a super-2 number, since 2×21004550439² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004550339) 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, 3500758404 + ... + 3500758409.

It is an arithmetic number, because the mean of its divisors is an integer number (7001516814).

Almost surely, 2^21004550439 is an apocalyptic number.

21004550439 is a deficient number, since it is larger than the sum of its proper divisors (7001516817).

21004550439 is an equidigital number, since it uses as much as digits as its factorization.

21004550439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7001516816.

The product of its (nonzero) digits is 21600, while the sum is 33.

The spelling of 21004550439 in words is "twenty-one billion, four million, five hundred fifty thousand, four hundred thirty-nine".