21043551239 has 4 divisors (see below), whose sum is σ = 21091054056. Its totient is φ = 20996048424.

The previous prime is 21043551233. The next prime is 21043551301. The reversal of 21043551239 is 93215534012.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21043551239 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21043551199 and 21043551208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043551233) 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, 23750744 + ... + 23751629.

It is an arithmetic number, because the mean of its divisors is an integer number (5272763514).

Almost surely, 2^21043551239 is an apocalyptic number.

21043551239 is a deficient number, since it is larger than the sum of its proper divisors (47502817).

21043551239 is an equidigital number, since it uses as much as digits as its factorization.

21043551239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47502816.

The product of its (nonzero) digits is 32400, while the sum is 35.

The spelling of 21043551239 in words is "twenty-one billion, forty-three million, five hundred fifty-one thousand, two hundred thirty-nine".