261334557 has 48 divisors (see below), whose sum is σ = 450178560. Its totient is φ = 144230400.

The previous prime is 261334543. The next prime is 261334559. The reversal of 261334557 is 755433162.

261334557 is a `hidden beast` number, since 2 + 613 + 34 + 5 + 5 + 7 = 666.

It is not a de Polignac number, because 261334557 - 2¹⁰ = 261333533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261334559) 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, 49669 + ... + 54677.

It is an arithmetic number, because the mean of its divisors is an integer number (9378720).

Almost surely, 2^261334557 is an apocalyptic number.

It is an amenable number.

261334557 is a deficient number, since it is larger than the sum of its proper divisors (188844003).

261334557 is a wasteful number, since it uses less digits than its factorization.

261334557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5074 (or 5071 counting only the distinct ones).

The product of its digits is 75600, while the sum is 36.

The square root of 261334557 is about 16165.8453846373. The cubic root of 261334557 is about 639.3405944341.

The spelling of 261334557 in words is "two hundred sixty-one million, three hundred thirty-four thousand, five hundred fifty-seven".