21115665204206 has 8 divisors (see below), whose sum is σ = 31764252815400. Its totient is φ = 10527580932408.

The previous prime is 21115665204187. The next prime is 21115665204233. The reversal of 21115665204206 is 60240256651112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21115665204206² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15125833976 + ... + 15125835371.

It is an arithmetic number, because the mean of its divisors is an integer number (3970531601925).

Almost surely, 2^{21115665204206} is an apocalyptic number.

21115665204206 is a deficient number, since it is larger than the sum of its proper divisors (10648587611194).

21115665204206 is a wasteful number, since it uses less digits than its factorization.

21115665204206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30251669698.

The product of its (nonzero) digits is 172800, while the sum is 41.

The spelling of 21115665204206 in words is "twenty-one trillion, one hundred fifteen billion, six hundred sixty-five million, two hundred four thousand, two hundred six".