261381251 has 4 divisors (see below), whose sum is σ = 262735752. Its totient is φ = 260026752.

The previous prime is 261381187. The next prime is 261381257. The reversal of 261381251 is 152183162.

261381251 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 261381251 - 2⁶ = 261381187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261381257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 676961 + ... + 677346.

It is an arithmetic number, because the mean of its divisors is an integer number (65683938).

Almost surely, 2^261381251 is an apocalyptic number.

261381251 is a deficient number, since it is larger than the sum of its proper divisors (1354501).

261381251 is a wasteful number, since it uses less digits than its factorization.

261381251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354500.

The product of its digits is 2880, while the sum is 29.

The square root of 261381251 is about 16167.2895378292. The cubic root of 261381251 is about 639.3786702658.

The spelling of 261381251 in words is "two hundred sixty-one million, three hundred eighty-one thousand, two hundred fifty-one".