261752661 has 16 divisors (see below), whose sum is σ = 388108800. Its totient is φ = 174354624.

The previous prime is 261752629. The next prime is 261752663. The reversal of 261752661 is 166257162.

It is a happy number.

It is not a de Polignac number, because 261752661 - 2⁵ = 261752629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261752663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35485 + ... + 42221.

It is an arithmetic number, because the mean of its divisors is an integer number (24256800).

Almost surely, 2^261752661 is an apocalyptic number.

It is an amenable number.

261752661 is a deficient number, since it is larger than the sum of its proper divisors (126356139).

261752661 is a wasteful number, since it uses less digits than its factorization.

261752661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8185 (or 8179 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 261752661 is about 16178.7719249639. The cubic root of 261752661 is about 639.6813688988.

It can be divided in two parts, 2617 and 52661, that added together give a triangular number (55278 = T₃₃₂).

The spelling of 261752661 in words is "two hundred sixty-one million, seven hundred fifty-two thousand, six hundred sixty-one".