261642646005 has 256 divisors, whose sum is σ = 492853788672. Its totient is φ = 117573120000.

The previous prime is 261642645997. The next prime is 261642646043. The reversal of 261642646005 is 500646246162.

It is not a de Polignac number, because 261642646005 - 2³ = 261642645997 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 1732732680 + ... + 1732732830.

It is an arithmetic number, because the mean of its divisors is an integer number (1925210112).

Almost surely, 2^261642646005 is an apocalyptic number.

It is an amenable number.

261642646005 is a deficient number, since it is larger than the sum of its proper divisors (231211142667).

261642646005 is a wasteful number, since it uses less digits than its factorization.

261642646005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 428.

The product of its (nonzero) digits is 414720, while the sum is 42.

The spelling of 261642646005 in words is "two hundred sixty-one billion, six hundred forty-two million, six hundred forty-six thousand, five".