163811621 has 2 divisors, whose sum is σ = 163811622. Its totient is φ = 163811620.

The previous prime is 163811603. The next prime is 163811651. The reversal of 163811621 is 126118361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 146289025 + 17522596 = 12095^2 + 4186^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-163811621 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163811651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81905810 + 81905811.

It is an arithmetic number, because the mean of its divisors is an integer number (81905811).

Almost surely, 2^163811621 is an apocalyptic number.

It is an amenable number.

163811621 is a deficient number, since it is larger than the sum of its proper divisors (1).

163811621 is an equidigital number, since it uses as much as digits as its factorization.

163811621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 29.

The square root of 163811621 is about 12798.8913973047. The cubic root of 163811621 is about 547.1607077481.

Adding to 163811621 its reverse (126118361), we get a palindrome (289929982).

The spelling of 163811621 in words is "one hundred sixty-three million, eight hundred eleven thousand, six hundred twenty-one".