261206057 has 4 divisors (see below), whose sum is σ = 298521216. Its totient is φ = 223890900.

The previous prime is 261206027. The next prime is 261206059. The reversal of 261206057 is 750602162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 750602162 = 2 ⋅375301081.

It is a cyclic number.

It is not a de Polignac number, because 261206057 - 2⁸ = 261205801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261206059) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 18657569 + ... + 18657582.

It is an arithmetic number, because the mean of its divisors is an integer number (74630304).

Almost surely, 2^261206057 is an apocalyptic number.

It is an amenable number.

261206057 is a deficient number, since it is larger than the sum of its proper divisors (37315159).

261206057 is an equidigital number, since it uses as much as digits as its factorization.

261206057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37315158.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 261206057 is about 16161.8704672448. The cubic root of 261206057 is about 639.2357878642.

The spelling of 261206057 in words is "two hundred sixty-one million, two hundred six thousand, fifty-seven".