261018251 has 8 divisors (see below), whose sum is σ = 281397984. Its totient is φ = 240681600.

The previous prime is 261018227. The next prime is 261018271. The reversal of 261018251 is 152810162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261018251 - 2¹⁸ = 260756107 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261018251.

It is not an unprimeable number, because it can be changed into a prime (261018271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2426 + ... + 22976.

It is an arithmetic number, because the mean of its divisors is an integer number (35174748).

Almost surely, 2^261018251 is an apocalyptic number.

261018251 is a deficient number, since it is larger than the sum of its proper divisors (20379733).

261018251 is a wasteful number, since it uses less digits than its factorization.

261018251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21541.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 261018251 is about 16156.0592657987. The cubic root of 261018251 is about 639.0825485639.

The spelling of 261018251 in words is "two hundred sixty-one million, eighteen thousand, two hundred fifty-one".