21115333061665 has 16 divisors (see below), whose sum is σ = 26778262633920. Its totient is φ = 15939442008000.

The previous prime is 21115333061659. The next prime is 21115333061723. The reversal of 21115333061665 is 56616033351112.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21115333061665 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 442738434 + ... + 442786123.

It is an arithmetic number, because the mean of its divisors is an integer number (1673641414620).

Almost surely, 2^{21115333061665} is an apocalyptic number.

It is an amenable number.

21115333061665 is a deficient number, since it is larger than the sum of its proper divisors (5662929572255).

21115333061665 is a wasteful number, since it uses less digits than its factorization.

21115333061665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 885524832.

The product of its (nonzero) digits is 291600, while the sum is 43.

The spelling of 21115333061665 in words is "twenty-one trillion, one hundred fifteen billion, three hundred thirty-three million, sixty-one thousand, six hundred sixty-five".