261655501551726 has 16 divisors (see below), whose sum is σ = 554094003286224. Its totient is φ = 82088000486784.

The previous prime is 261655501551671. The next prime is 261655501551739. The reversal of 261655501551726 is 627155105556162.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1282625007505 + ... + 1282625007708.

It is an arithmetic number, because the mean of its divisors is an integer number (34630875205389).

Almost surely, 2^{261655501551726} is an apocalyptic number.

261655501551726 is an abundant number, since it is smaller than the sum of its proper divisors (292438501734498).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261655501551726 is a wasteful number, since it uses less digits than its factorization.

261655501551726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2565250015235.

The product of its (nonzero) digits is 18900000, while the sum is 57.

The spelling of 261655501551726 in words is "two hundred sixty-one trillion, six hundred fifty-five billion, five hundred one million, five hundred fifty-one thousand, seven hundred twenty-six".