1671561197 has 2 divisors, whose sum is σ = 1671561198. Its totient is φ = 1671561196.

The previous prime is 1671561187. The next prime is 1671561239. The reversal of 1671561197 is 7911651761.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1667007241 + 4553956 = 40829^2 + 2134^2 .

It is a cyclic number.

It is not a de Polignac number, because 1671561197 - 2²⁰ = 1670512621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1671561127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 835780598 + 835780599.

It is an arithmetic number, because the mean of its divisors is an integer number (835780599).

Almost surely, 2^1671561197 is an apocalyptic number.

It is an amenable number.

1671561197 is a deficient number, since it is larger than the sum of its proper divisors (1).

1671561197 is an equidigital number, since it uses as much as digits as its factorization.

1671561197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 79380, while the sum is 44.

The square root of 1671561197 is about 40884.7306093608. The cubic root of 1671561197 is about 1186.7905886854.

The spelling of 1671561197 in words is "one billion, six hundred seventy-one million, five hundred sixty-one thousand, one hundred ninety-seven".