261988147 has 4 divisors (see below), whose sum is σ = 273378960. Its totient is φ = 250597336.

The previous prime is 261988141. The next prime is 261988151. The reversal of 261988147 is 741889162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261988147 - 2²³ = 253599539 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261988097 and 261988106.

It is not an unprimeable number, because it can be changed into a prime (261988141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5695372 + ... + 5695417.

It is an arithmetic number, because the mean of its divisors is an integer number (68344740).

Almost surely, 2^261988147 is an apocalyptic number.

261988147 is a deficient number, since it is larger than the sum of its proper divisors (11390813).

261988147 is a wasteful number, since it uses less digits than its factorization.

261988147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11390812.

The product of its digits is 193536, while the sum is 46.

The square root of 261988147 is about 16186.0479117047. The cubic root of 261988147 is about 639.8731413601.

The spelling of 261988147 in words is "two hundred sixty-one million, nine hundred eighty-eight thousand, one hundred forty-seven".