21068661772 has 6 divisors (see below), whose sum is σ = 36870158108. Its totient is φ = 10534330884.

The previous prime is 21068661763. The next prime is 21068661773. The reversal of 21068661772 is 27716686012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21068661773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2633582718 + ... + 2633582725.

Almost surely, 2^21068661772 is an apocalyptic number.

It is an amenable number.

21068661772 is a deficient number, since it is larger than the sum of its proper divisors (15801496336).

21068661772 is a wasteful number, since it uses less digits than its factorization.

21068661772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5267165447 (or 5267165445 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 46.

The spelling of 21068661772 in words is "twenty-one billion, sixty-eight million, six hundred sixty-one thousand, seven hundred seventy-two".