261139947 has 16 divisors (see below), whose sum is σ = 359305632. Its totient is φ = 168596480.

The previous prime is 261139927. The next prime is 261139961. The reversal of 261139947 is 749931162.

It is a cyclic number.

It is not a de Polignac number, because 261139947 - 2¹² = 261135851 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261139899 and 261139908.

It is not an unprimeable number, because it can be changed into a prime (261139927) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 9103 + ... + 24599.

It is an arithmetic number, because the mean of its divisors is an integer number (22456602).

Almost surely, 2^261139947 is an apocalyptic number.

261139947 is a deficient number, since it is larger than the sum of its proper divisors (98165685).

261139947 is a wasteful number, since it uses less digits than its factorization.

261139947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15678.

The product of its digits is 81648, while the sum is 42.

The square root of 261139947 is about 16159.8250918752. The cubic root of 261139947 is about 639.1818541434.

The spelling of 261139947 in words is "two hundred sixty-one million, one hundred thirty-nine thousand, nine hundred forty-seven".