261251378 has 16 divisors (see below), whose sum is σ = 398960640. Its totient is φ = 128280096.

The previous prime is 261251377. The next prime is 261251407. The reversal of 261251378 is 873152162.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (261251377) 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 7 ways as a sum of consecutive naturals, for example, 31151 + ... + 38637.

It is an arithmetic number, because the mean of its divisors is an integer number (24935040).

Almost surely, 2^261251378 is an apocalyptic number.

261251378 is a deficient number, since it is larger than the sum of its proper divisors (137709262).

261251378 is a wasteful number, since it uses less digits than its factorization.

261251378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7801.

The product of its digits is 20160, while the sum is 35.

The square root of 261251378 is about 16163.2725028071. The cubic root of 261251378 is about 639.2727562894.

The spelling of 261251378 in words is "two hundred sixty-one million, two hundred fifty-one thousand, three hundred seventy-eight".