21555612835309 has 32 divisors (see below), whose sum is σ = 25844744701440. Its totient is φ = 17586960518400.

The previous prime is 21555612835297. The next prime is 21555612835363. The reversal of 21555612835309 is 90353821655512.

It is not a de Polignac number, because 21555612835309 - 2¹⁹ = 21555612311021 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21555612835309.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555612835109) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 517881519 + ... + 517923139.

It is an arithmetic number, because the mean of its divisors is an integer number (807648271920).

Almost surely, 2^{21555612835309} is an apocalyptic number.

21555612835309 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21555612835309 is a deficient number, since it is larger than the sum of its proper divisors (4289131866131).

21555612835309 is a wasteful number, since it uses less digits than its factorization.

21555612835309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77661.

The product of its (nonzero) digits is 9720000, while the sum is 55.

The spelling of 21555612835309 in words is "twenty-one trillion, five hundred fifty-five billion, six hundred twelve million, eight hundred thirty-five thousand, three hundred nine".