261275378125 has 24 divisors (see below), whose sum is σ = 326668545000. Its totient is φ = 208959360000.

The previous prime is 261275378107. The next prime is 261275378183. The reversal of 261275378125 is 521873572162.

It can be written as a sum of positive squares in 12 ways, for example, as 260837982729 + 437395396 = 510723^2 + 20914^2 .

It is not a de Polignac number, because 261275378125 - 2³³ = 252685443533 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12893001 + ... + 12913249.

It is an arithmetic number, because the mean of its divisors is an integer number (13611189375).

Almost surely, 2^261275378125 is an apocalyptic number.

261275378125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261275378125 is a deficient number, since it is larger than the sum of its proper divisors (65393166875).

261275378125 is an frugal number, since it uses more digits than its factorization.

261275378125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24403 (or 24383 counting only the distinct ones).

The product of its digits is 1411200, while the sum is 49.

The spelling of 261275378125 in words is "two hundred sixty-one billion, two hundred seventy-five million, three hundred seventy-eight thousand, one hundred twenty-five".