261384381 has 8 divisors (see below), whose sum is σ = 387236160. Its totient is φ = 174256236.

The previous prime is 261384379. The next prime is 261384407. The reversal of 261384381 is 183483162.

261384381 is a `hidden beast` number, since 2 + 613 + 8 + 4 + 38 + 1 = 666.

It is not a de Polignac number, because 261384381 - 2¹ = 261384379 is a prime.

It is a super-2 number, since 2×261384381² = 136643589261506322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261386381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4840425 + ... + 4840478.

It is an arithmetic number, because the mean of its divisors is an integer number (48404520).

Almost surely, 2^261384381 is an apocalyptic number.

It is an amenable number.

261384381 is a deficient number, since it is larger than the sum of its proper divisors (125851779).

261384381 is an equidigital number, since it uses as much as digits as its factorization.

261384381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9680912 (or 9680906 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 261384381 is about 16167.3863379335. The cubic root of 261384381 is about 639.3812224092.

The spelling of 261384381 in words is "two hundred sixty-one million, three hundred eighty-four thousand, three hundred eighty-one".