161947451 has 2 divisors, whose sum is σ = 161947452. Its totient is φ = 161947450.

The previous prime is 161947447. The next prime is 161947481. The reversal of 161947451 is 154749161.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161947451 - 2² = 161947447 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161947411) 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, 80973725 + 80973726.

It is an arithmetic number, because the mean of its divisors is an integer number (80973726).

Almost surely, 2^161947451 is an apocalyptic number.

161947451 is a deficient number, since it is larger than the sum of its proper divisors (1).

161947451 is an equidigital number, since it uses as much as digits as its factorization.

161947451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 38.

The square root of 161947451 is about 12725.8575742462. The cubic root of 161947451 is about 545.0772283456.

The spelling of 161947451 in words is "one hundred sixty-one million, nine hundred forty-seven thousand, four hundred fifty-one".