161933021 has 2 divisors, whose sum is σ = 161933022. Its totient is φ = 161933020.

The previous prime is 161932963. The next prime is 161933027. The reversal of 161933021 is 120339161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161925625 + 7396 = 12725^2 + 86^2 .

It is a cyclic number.

It is not a de Polignac number, because 161933021 - 2⁶ = 161932957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161933027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80966510 + 80966511.

It is an arithmetic number, because the mean of its divisors is an integer number (80966511).

Almost surely, 2^161933021 is an apocalyptic number.

It is an amenable number.

161933021 is a deficient number, since it is larger than the sum of its proper divisors (1).

161933021 is an equidigital number, since it uses as much as digits as its factorization.

161933021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 161933021 is about 12725.2906057190. The cubic root of 161933021 is about 545.0610385301.

The spelling of 161933021 in words is "one hundred sixty-one million, nine hundred thirty-three thousand, twenty-one".