161601637 has 2 divisors, whose sum is σ = 161601638. Its totient is φ = 161601636.

The previous prime is 161601619. The next prime is 161601641. The reversal of 161601637 is 736106161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161442436 + 159201 = 12706^2 + 399^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161601637 is a prime.

It is a super-2 number, since 2×161601637² = 52230178162159538, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161601599 and 161601608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161601617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80800818 + 80800819.

It is an arithmetic number, because the mean of its divisors is an integer number (80800819).

Almost surely, 2^161601637 is an apocalyptic number.

It is an amenable number.

161601637 is a deficient number, since it is larger than the sum of its proper divisors (1).

161601637 is an equidigital number, since it uses as much as digits as its factorization.

161601637 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 161601637 is about 12712.2632524661. The cubic root of 161601637 is about 544.6889755255.

Adding to 161601637 its reverse (736106161), we get a palindrome (897707798).

The spelling of 161601637 in words is "one hundred sixty-one million, six hundred one thousand, six hundred thirty-seven".