161236021 has 2 divisors, whose sum is σ = 161236022. Its totient is φ = 161236020.

The previous prime is 161236013. The next prime is 161236043. The reversal of 161236021 is 120632161.

It is an a-pointer prime, because the next prime (161236043) can be obtained adding 161236021 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 92428996 + 68807025 = 9614^2 + 8295^2 .

It is a cyclic number.

It is not a de Polignac number, because 161236021 - 2³ = 161236013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161235983 and 161236001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161236001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80618010 + 80618011.

It is an arithmetic number, because the mean of its divisors is an integer number (80618011).

Almost surely, 2^161236021 is an apocalyptic number.

It is an amenable number.

161236021 is a deficient number, since it is larger than the sum of its proper divisors (1).

161236021 is an equidigital number, since it uses as much as digits as its factorization.

161236021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 161236021 is about 12697.8746646831. The cubic root of 161236021 is about 544.2778877335.

Adding to 161236021 its reverse (120632161), we get a palindrome (281868182).

The spelling of 161236021 in words is "one hundred sixty-one million, two hundred thirty-six thousand, twenty-one".