261907385 has 8 divisors (see below), whose sum is σ = 321954696. Its totient is φ = 204415360.

The previous prime is 261907361. The next prime is 261907487. The reversal of 261907385 is 583709162.

261907385 = 11443² + 11444².

It can be written as a sum of positive squares in 4 ways, for example, as 5234944 + 256672441 = 2288^2 + 16021^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261907385 - 2¹² = 261903289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 638594 + ... + 639003.

It is an arithmetic number, because the mean of its divisors is an integer number (40244337).

Almost surely, 2^261907385 is an apocalyptic number.

261907385 is the 11444-th centered square number.

It is an amenable number.

261907385 is a deficient number, since it is larger than the sum of its proper divisors (60047311).

261907385 is a wasteful number, since it uses less digits than its factorization.

261907385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277643.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 261907385 is about 16183.5529164643. The cubic root of 261907385 is about 639.8073842558.

The spelling of 261907385 in words is "two hundred sixty-one million, nine hundred seven thousand, three hundred eighty-five".