261771506723406 has 16 divisors (see below), whose sum is σ = 528435938807424. Its totient is φ = 86441681347704.

The previous prime is 261771506723357. The next prime is 261771506723471. The reversal of 261771506723406 is 604327605177162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 203871889330 + ... + 203871890613.

It is an arithmetic number, because the mean of its divisors is an integer number (33027246175464).

Almost surely, 2^{261771506723406} is an apocalyptic number.

261771506723406 is an abundant number, since it is smaller than the sum of its proper divisors (266664432084018).

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

261771506723406 is a wasteful number, since it uses less digits than its factorization.

261771506723406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407743780055.

The product of its (nonzero) digits is 17781120, while the sum is 57.

The spelling of 261771506723406 in words is "two hundred sixty-one trillion, seven hundred seventy-one billion, five hundred six million, seven hundred twenty-three thousand, four hundred six".