21828117555 has 48 divisors (see below), whose sum is σ = 40187837664. Its totient is φ = 10922173440.

The previous prime is 21828117541. The next prime is 21828117559. The reversal of 21828117555 is 55571182812.

It is a happy number.

21828117555 is a `hidden beast` number, since 2 + 1 + 8 + 2 + 81 + 17 + 555 = 666.

It is not a de Polignac number, because 21828117555 - 2⁴ = 21828117539 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21828117555.

It is not an unprimeable number, because it can be changed into a prime (21828117559) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 197500 + ... + 287510.

It is an arithmetic number, because the mean of its divisors is an integer number (837246618).

Almost surely, 2^21828117555 is an apocalyptic number.

21828117555 is a deficient number, since it is larger than the sum of its proper divisors (18359720109).

21828117555 is a wasteful number, since it uses less digits than its factorization.

21828117555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90356 (or 90353 counting only the distinct ones).

The product of its digits is 224000, while the sum is 45.

The spelling of 21828117555 in words is "twenty-one billion, eight hundred twenty-eight million, one hundred seventeen thousand, five hundred fifty-five".