21166641560365 has 16 divisors (see below), whose sum is σ = 30556354734720. Its totient is φ = 13750359629760.

The previous prime is 21166641560357. The next prime is 21166641560399. The reversal of 21166641560365 is 56306514666112.

It is a happy number.

It is not a de Polignac number, because 21166641560365 - 2³ = 21166641560357 is a prime.

It is a congruent number.

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, 15914767426 + ... + 15914768755.

It is an arithmetic number, because the mean of its divisors is an integer number (1909772170920).

Almost surely, 2^{21166641560365} is an apocalyptic number.

It is an amenable number.

21166641560365 is a deficient number, since it is larger than the sum of its proper divisors (9389713174355).

21166641560365 is a wasteful number, since it uses less digits than its factorization.

21166641560365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31829536212.

The product of its (nonzero) digits is 4665600, while the sum is 52.

The spelling of 21166641560365 in words is "twenty-one trillion, one hundred sixty-six billion, six hundred forty-one million, five hundred sixty thousand, three hundred sixty-five".