21533919218 has 16 divisors (see below), whose sum is σ = 37700722944. Its totient is φ = 9032464320.

The previous prime is 21533919163. The next prime is 21533919269. The reversal of 21533919218 is 81291933512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16362503 + ... + 16363818.

It is an arithmetic number, because the mean of its divisors is an integer number (2356295184).

Almost surely, 2^21533919218 is an apocalyptic number.

21533919218 is a deficient number, since it is larger than the sum of its proper divisors (16166803726).

21533919218 is a wasteful number, since it uses less digits than its factorization.

21533919218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32726377.

The product of its digits is 116640, while the sum is 44.

The spelling of 21533919218 in words is "twenty-one billion, five hundred thirty-three million, nine hundred nineteen thousand, two hundred eighteen".