165621210201663 has 16 divisors (see below), whose sum is σ = 234777236451840. Its totient is φ = 103620817318304.

The previous prime is 165621210201659. The next prime is 165621210201731. The reversal of 165621210201663 is 366102012126561.

It is a cyclic number.

It is not a de Polignac number, because 165621210201663 - 2² = 165621210201659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165621210206663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22644405723 + ... + 22644413036.

It is an arithmetic number, because the mean of its divisors is an integer number (14673577278240).

Almost surely, 2^{165621210201663} is an apocalyptic number.

165621210201663 is a deficient number, since it is larger than the sum of its proper divisors (69156026250177).

165621210201663 is a wasteful number, since it uses less digits than its factorization.

165621210201663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45288818838.

The product of its (nonzero) digits is 155520, while the sum is 42.

The spelling of 165621210201663 in words is "one hundred sixty-five trillion, six hundred twenty-one billion, two hundred ten million, two hundred one thousand, six hundred sixty-three".