261205351 has 4 divisors (see below), whose sum is σ = 284951304. Its totient is φ = 237459400.

The previous prime is 261205337. The next prime is 261205361. The reversal of 261205351 is 153502162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261205351 - 2²³ = 252816743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261205361) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 11872960 + ... + 11872981.

It is an arithmetic number, because the mean of its divisors is an integer number (71237826).

Almost surely, 2^261205351 is an apocalyptic number.

261205351 is a deficient number, since it is larger than the sum of its proper divisors (23745953).

261205351 is a wasteful number, since it uses less digits than its factorization.

261205351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23745952.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 261205351 is about 16161.8486256987. The cubic root of 261205351 is about 639.2352119449.

The spelling of 261205351 in words is "two hundred sixty-one million, two hundred five thousand, three hundred fifty-one".