261872149 has 24 divisors (see below), whose sum is σ = 332457408. Its totient is φ = 200392320.

The previous prime is 261872147. The next prime is 261872179. The reversal of 261872149 is 941278162.

It is not a de Polignac number, because 261872149 - 2¹ = 261872147 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261872147) 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 23 ways as a sum of consecutive naturals, for example, 267549 + ... + 268525.

It is an arithmetic number, because the mean of its divisors is an integer number (13852392).

Almost surely, 2^261872149 is an apocalyptic number.

It is an amenable number.

261872149 is a deficient number, since it is larger than the sum of its proper divisors (70585259).

261872149 is an equidigital number, since it uses as much as digits as its factorization.

261872149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113 (or 1054 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 261872149 is about 16182.4642437424. The cubic root of 261872149 is about 639.7786905708.

The spelling of 261872149 in words is "two hundred sixty-one million, eight hundred seventy-two thousand, one hundred forty-nine".