261731502278 has 4 divisors (see below), whose sum is σ = 392597253420. Its totient is φ = 130865751138.

The previous prime is 261731502233. The next prime is 261731502283. The reversal of 261731502278 is 872205137162.

261731502278 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 congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65432875568 + ... + 65432875571.

It is an arithmetic number, because the mean of its divisors is an integer number (98149313355).

Almost surely, 2^261731502278 is an apocalyptic number.

261731502278 is a deficient number, since it is larger than the sum of its proper divisors (130865751142).

261731502278 is a wasteful number, since it uses less digits than its factorization.

261731502278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130865751141.

The product of its (nonzero) digits is 282240, while the sum is 44.

The spelling of 261731502278 in words is "two hundred sixty-one billion, seven hundred thirty-one million, five hundred two thousand, two hundred seventy-eight".