261916569 has 48 divisors (see below), whose sum is σ = 420323904. Its totient is φ = 156441600.

The previous prime is 261916561. The next prime is 261916573. The reversal of 261916569 is 965619162.

It is a happy number.

It is not a de Polignac number, because 261916569 - 2³ = 261916561 is a prime.

It is a super-2 number, since 2×261916569² = 137200578233463522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261916561) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 269254 + ... + 270224.

It is an arithmetic number, because the mean of its divisors is an integer number (8756748).

Almost surely, 2^261916569 is an apocalyptic number.

It is an amenable number.

261916569 is a deficient number, since it is larger than the sum of its proper divisors (158407335).

261916569 is a wasteful number, since it uses less digits than its factorization.

261916569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078 (or 1075 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 261916569 is about 16183.8366588396. The cubic root of 261916569 is about 639.8148626275.

The spelling of 261916569 in words is "two hundred sixty-one million, nine hundred sixteen thousand, five hundred sixty-nine".