165821428799 has 16 divisors (see below), whose sum is σ = 188617346400. Its totient is φ = 144514855296.

The previous prime is 165821428793. The next prime is 165821428831. The reversal of 165821428799 is 997824128561.

It is a cyclic number.

It is not a de Polignac number, because 165821428799 - 2⁴ = 165821428783 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165821428793) 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, 1073264 + ... + 1218005.

It is an arithmetic number, because the mean of its divisors is an integer number (11788584150).

Almost surely, 2^165821428799 is an apocalyptic number.

165821428799 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

165821428799 is a deficient number, since it is larger than the sum of its proper divisors (22795917601).

165821428799 is a wasteful number, since it uses less digits than its factorization.

165821428799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2291594.

The product of its digits is 17418240, while the sum is 62.

The spelling of 165821428799 in words is "one hundred sixty-five billion, eight hundred twenty-one million, four hundred twenty-eight thousand, seven hundred ninety-nine".