261611764 has 6 divisors (see below), whose sum is σ = 457820594. Its totient is φ = 130805880.

The previous prime is 261611743. The next prime is 261611807. The reversal of 261611764 is 467116162.

It can be written as a sum of positive squares in only one way, i.e., 183819364 + 77792400 = 13558^2 + 8820^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32701467 + ... + 32701474.

Almost surely, 2^261611764 is an apocalyptic number.

It is an amenable number.

261611764 is a deficient number, since it is larger than the sum of its proper divisors (196208830).

261611764 is a wasteful number, since it uses less digits than its factorization.

261611764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65402945 (or 65402943 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 261611764 is about 16174.4169601256. The cubic root of 261611764 is about 639.5665717693.

The spelling of 261611764 in words is "two hundred sixty-one million, six hundred eleven thousand, seven hundred sixty-four".