21555616229 has 8 divisors (see below), whose sum is σ = 25429667328. Its totient is φ = 17880234480.

The previous prime is 21555616211. The next prime is 21555616249. The reversal of 21555616229 is 92261655512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21555616229 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21555616229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555616249) 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, 49667102 + ... + 49667535.

It is an arithmetic number, because the mean of its divisors is an integer number (3178708416).

Almost surely, 2^21555616229 is an apocalyptic number.

It is an amenable number.

21555616229 is a deficient number, since it is larger than the sum of its proper divisors (3874051099).

21555616229 is an equidigital number, since it uses as much as digits as its factorization.

21555616229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99334675.

The product of its digits is 324000, while the sum is 44.

The spelling of 21555616229 in words is "twenty-one billion, five hundred fifty-five million, six hundred sixteen thousand, two hundred twenty-nine".