21733961818 has 4 divisors (see below), whose sum is σ = 32600942730. Its totient is φ = 10866980908.

The previous prime is 21733961783. The next prime is 21733961827. The reversal of 21733961818 is 81816933712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14214123729 + 7519838089 = 119223^2 + 86717^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5433490453 + ... + 5433490456.

Almost surely, 2^21733961818 is an apocalyptic number.

21733961818 is a deficient number, since it is larger than the sum of its proper divisors (10866980912).

21733961818 is a wasteful number, since it uses less digits than its factorization.

21733961818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10866980911.

The product of its digits is 435456, while the sum is 49.

The spelling of 21733961818 in words is "twenty-one billion, seven hundred thirty-three million, nine hundred sixty-one thousand, eight hundred eighteen".