161287421 has 2 divisors, whose sum is σ = 161287422. Its totient is φ = 161287420.

The previous prime is 161287397. The next prime is 161287433. The reversal of 161287421 is 124782161.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156600196 + 4687225 = 12514^2 + 2165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161287421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161280421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80643710 + 80643711.

It is an arithmetic number, because the mean of its divisors is an integer number (80643711).

Almost surely, 2^161287421 is an apocalyptic number.

It is an amenable number.

161287421 is a deficient number, since it is larger than the sum of its proper divisors (1).

161287421 is an equidigital number, since it uses as much as digits as its factorization.

161287421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 32.

The square root of 161287421 is about 12699.8984641610. The cubic root of 161287421 is about 544.3357178862.

The spelling of 161287421 in words is "one hundred sixty-one million, two hundred eighty-seven thousand, four hundred twenty-one".