167561691649 has 45 divisors (see below), whose sum is σ = 196785497235. Its totient is φ = 142647848640.

The previous prime is 167561691631. The next prime is 167561691697. The reversal of 167561691649 is 946196165761.

The square root of 167561691649 is 409343.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 130454604225 + 37107087424 = 361185^2 + 192632^2 .

It is not a de Polignac number, because 167561691649 - 2²⁷ = 167427473921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (167561694649) 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 in 44 ways as a sum of consecutive naturals, for example, 842018452 + ... + 842018650.

Almost surely, 2^167561691649 is an apocalyptic number.

167561691649 is the 409343-rd square number.

167561691649 is the 204672-nd centered octagonal number.

It is an amenable number.

167561691649 is a deficient number, since it is larger than the sum of its proper divisors (29223805586).

167561691649 is an frugal number, since it uses more digits than its factorization.

167561691649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476 (or 227 counting only the distinct ones).

The product of its digits is 14696640, while the sum is 61.

The spelling of 167561691649 in words is "one hundred sixty-seven billion, five hundred sixty-one million, six hundred ninety-one thousand, six hundred forty-nine".