163995821 has 32 divisors (see below), whose sum is σ = 201813120. Its totient is φ = 131328000.

The previous prime is 163995809. The next prime is 163995823. The reversal of 163995821 is 128599361.

It is a happy number.

It is not a de Polignac number, because 163995821 - 2⁶ = 163995757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163995823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 358625 + ... + 359081.

It is an arithmetic number, because the mean of its divisors is an integer number (6306660).

Almost surely, 2^163995821 is an apocalyptic number.

163995821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

163995821 is a deficient number, since it is larger than the sum of its proper divisors (37817299).

163995821 is a wasteful number, since it uses less digits than its factorization.

163995821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605.

The product of its digits is 116640, while the sum is 44.

The square root of 163995821 is about 12806.0853112885. The cubic root of 163995821 is about 547.3657181299.

The spelling of 163995821 in words is "one hundred sixty-three million, nine hundred ninety-five thousand, eight hundred twenty-one".