21555145233 has 12 divisors (see below), whose sum is σ = 31144555728. Its totient is φ = 14365783320.

The previous prime is 21555145207. The next prime is 21555145237. The reversal of 21555145233 is 33254155512.

21555145233 is a `hidden beast` number, since 2 + 155 + 51 + 452 + 3 + 3 = 666.

It is not a de Polignac number, because 21555145233 - 2¹³ = 21555137041 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21555145237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 327663 + ... + 387908.

It is an arithmetic number, because the mean of its divisors is an integer number (2595379644).

Almost surely, 2^21555145233 is an apocalyptic number.

It is an amenable number.

21555145233 is a deficient number, since it is larger than the sum of its proper divisors (9589410495).

21555145233 is a wasteful number, since it uses less digits than its factorization.

21555145233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718924 (or 718921 counting only the distinct ones).

The product of its digits is 90000, while the sum is 36.

The spelling of 21555145233 in words is "twenty-one billion, five hundred fifty-five million, one hundred forty-five thousand, two hundred thirty-three".