261138758601 has 16 divisors (see below), whose sum is σ = 398145512448. Its totient is φ = 149139728400.

The previous prime is 261138758561. The next prime is 261138758611. The reversal of 261138758601 is 106857831162.

It is not a de Polignac number, because 261138758601 - 2²² = 261134564297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261138758611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3395205 + ... + 3471266.

It is an arithmetic number, because the mean of its divisors is an integer number (24884094528).

Almost surely, 2^261138758601 is an apocalyptic number.

261138758601 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

261138758601 is a deficient number, since it is larger than the sum of its proper divisors (137006753847).

261138758601 is a wasteful number, since it uses less digits than its factorization.

261138758601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6868292.

The product of its (nonzero) digits is 483840, while the sum is 48.

The spelling of 261138758601 in words is "two hundred sixty-one billion, one hundred thirty-eight million, seven hundred fifty-eight thousand, six hundred one".