21233045556 has 18 divisors (see below), whose sum is σ = 53672420802. Its totient is φ = 7077681840.

The previous prime is 21233045531. The next prime is 21233045597. The reversal of 21233045556 is 65554033212.

21233045556 is a `hidden beast` number, since 2 + 123 + 30 + 455 + 56 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14013824400 + 7219221156 = 118380^2 + 84966^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 589806821 = 21233045556 / (2 + 1 + 2 + 3 + 3 + 0 + 4 + 5 + 5 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 21233045556.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 294903375 + ... + 294903446.

Almost surely, 2^21233045556 is an apocalyptic number.

It is an amenable number.

21233045556 is an abundant number, since it is smaller than the sum of its proper divisors (32439375246).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21233045556 is a wasteful number, since it uses less digits than its factorization.

21233045556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589806831 (or 589806826 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 36.

Adding to 21233045556 its reverse (65554033212), we get a palindrome (86787078768).

The spelling of 21233045556 in words is "twenty-one billion, two hundred thirty-three million, forty-five thousand, five hundred fifty-six".