161421523 has 2 divisors, whose sum is σ = 161421524. Its totient is φ = 161421522.

The previous prime is 161421509. The next prime is 161421539. The reversal of 161421523 is 325124161.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161421523 - 2²¹ = 159324371 is a prime.

It is a super-3 number, since 3×161421523³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (161421503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80710761 + 80710762.

It is an arithmetic number, because the mean of its divisors is an integer number (80710762).

Almost surely, 2^161421523 is an apocalyptic number.

161421523 is a deficient number, since it is larger than the sum of its proper divisors (1).

161421523 is an equidigital number, since it uses as much as digits as its factorization.

161421523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 161421523 is about 12705.1770156893. The cubic root of 161421523 is about 544.4865382590.

Adding to 161421523 its reverse (325124161), we get a palindrome (486545684).

The spelling of 161421523 in words is "one hundred sixty-one million, four hundred twenty-one thousand, five hundred twenty-three".