21554656199 has 16 divisors (see below), whose sum is σ = 22153824000. Its totient is φ = 20964655296.

The previous prime is 21554656187. The next prime is 21554656213. The reversal of 21554656199 is 99165645512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21554656199 - 2⁸ = 21554655943 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 21554656199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554656129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3626372 + ... + 3632310.

It is an arithmetic number, because the mean of its divisors is an integer number (1384614000).

Almost surely, 2^21554656199 is an apocalyptic number.

21554656199 is a deficient number, since it is larger than the sum of its proper divisors (599167801).

21554656199 is an equidigital number, since it uses as much as digits as its factorization.

21554656199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6694.

The product of its digits is 2916000, while the sum is 53.

The spelling of 21554656199 in words is "twenty-one billion, five hundred fifty-four million, six hundred fifty-six thousand, one hundred ninety-nine".