161221383 has 12 divisors (see below), whose sum is σ = 235824160. Its totient is φ = 106119936.

The previous prime is 161221369. The next prime is 161221393. The reversal of 161221383 is 383122161.

It is a happy number.

161221383 is a `hidden beast` number, since 1 + 61 + 221 + 383 = 666.

It is not a de Polignac number, because 161221383 - 2⁸ = 161221127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161221393) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 112666 + ... + 114087.

Almost surely, 2^161221383 is an apocalyptic number.

161221383 is a deficient number, since it is larger than the sum of its proper divisors (74602777).

161221383 is a wasteful number, since it uses less digits than its factorization.

161221383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226838 (or 226835 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 161221383 is about 12697.2982559283. The cubic root of 161221383 is about 544.2614162677.

It can be divided in two parts, 161221 and 383, that added together give a square (161604 = 402²).

The spelling of 161221383 in words is "one hundred sixty-one million, two hundred twenty-one thousand, three hundred eighty-three".