21538712833 has 8 divisors (see below), whose sum is σ = 23881971456. Its totient is φ = 19259653200.

The previous prime is 21538712831. The next prime is 21538712837. The reversal of 21538712833 is 33821783512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21538712833 - 2¹ = 21538712831 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21538712833.

It is not an unprimeable number, because it can be changed into a prime (21538712831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16049041 + ... + 16050382.

It is an arithmetic number, because the mean of its divisors is an integer number (2985246432).

Almost surely, 2^21538712833 is an apocalyptic number.

It is an amenable number.

21538712833 is a deficient number, since it is larger than the sum of its proper divisors (2343258623).

21538712833 is a wasteful number, since it uses less digits than its factorization.

21538712833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32099495.

The product of its digits is 241920, while the sum is 43.

The spelling of 21538712833 in words is "twenty-one billion, five hundred thirty-eight million, seven hundred twelve thousand, eight hundred thirty-three".