21200055539 has 4 divisors (see below), whose sum is σ = 22830829056. Its totient is φ = 19569282024.

The previous prime is 21200055511. The next prime is 21200055553. The reversal of 21200055539 is 93555000212.

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 21200055539 - 2¹² = 21200051443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21200055559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 815386739 + ... + 815386764.

It is an arithmetic number, because the mean of its divisors is an integer number (5707707264).

Almost surely, 2^21200055539 is an apocalyptic number.

21200055539 is a deficient number, since it is larger than the sum of its proper divisors (1630773517).

21200055539 is a wasteful number, since it uses less digits than its factorization.

21200055539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1630773516.

The product of its (nonzero) digits is 13500, while the sum is 32.

The spelling of 21200055539 in words is "twenty-one billion, two hundred million, fifty-five thousand, five hundred thirty-nine".