161136621 has 10 divisors (see below), whose sum is σ = 240710382. Its totient is φ = 107424360.

The previous prime is 161136617. The next prime is 161136629. The reversal of 161136621 is 126631161.

161136621 is a `hidden beast` number, since 1 + 6 + 1 + 1 + 36 + 621 = 666.

It can be written as a sum of positive squares in only one way, i.e., 148498596 + 12638025 = 12186^2 + 3555^2 .

It is not a de Polignac number, because 161136621 - 2² = 161136617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161136629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 994590 + ... + 994751.

Almost surely, 2^161136621 is an apocalyptic number.

It is an amenable number.

161136621 is a deficient number, since it is larger than the sum of its proper divisors (79573761).

161136621 is an equidigital number, since it uses as much as digits as its factorization.

161136621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989353 (or 1989344 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 161136621 is about 12693.9600204192. The cubic root of 161136621 is about 544.1660178939.

Adding to 161136621 its reverse (126631161), we get a palindrome (287767782).

The spelling of 161136621 in words is "one hundred sixty-one million, one hundred thirty-six thousand, six hundred twenty-one".