261198164 has 6 divisors (see below), whose sum is σ = 457096794. Its totient is φ = 130599080.

The previous prime is 261198131. The next prime is 261198181. The reversal of 261198164 is 461891162.

It can be written as a sum of positive squares in only one way, i.e., 233845264 + 27352900 = 15292^2 + 5230^2 .

It is a congruent number.

It is an unprimeable number.

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, 32649767 + ... + 32649774.

It is an arithmetic number, because the mean of its divisors is an integer number (76182799).

Almost surely, 2^261198164 is an apocalyptic number.

It is an amenable number.

261198164 is a deficient number, since it is larger than the sum of its proper divisors (195898630).

261198164 is a wasteful number, since it uses less digits than its factorization.

261198164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65299545 (or 65299543 counting only the distinct ones).

The product of its digits is 20736, while the sum is 38.

The square root of 261198164 is about 16161.6262795549. The cubic root of 261198164 is about 639.2293490920.

The spelling of 261198164 in words is "two hundred sixty-one million, one hundred ninety-eight thousand, one hundred sixty-four".