261400189 has 4 divisors (see below), whose sum is σ = 265685500. Its totient is φ = 257114880.

The previous prime is 261400169. The next prime is 261400201. The reversal of 261400189 is 981004162.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5560164 + 255840025 = 2358^2 + 15995^2 .

It is a cyclic number.

It is not a de Polignac number, because 261400189 - 2¹³ = 261391997 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261400189.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261400169) 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 3 ways as a sum of consecutive naturals, for example, 2142564 + ... + 2142685.

It is an arithmetic number, because the mean of its divisors is an integer number (66421375).

Almost surely, 2^261400189 is an apocalyptic number.

It is an amenable number.

261400189 is a deficient number, since it is larger than the sum of its proper divisors (4285311).

261400189 is an equidigital number, since it uses as much as digits as its factorization.

261400189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4285310.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 261400189 is about 16167.8752159955. The cubic root of 261400189 is about 639.3941116448.

The spelling of 261400189 in words is "two hundred sixty-one million, four hundred thousand, one hundred eighty-nine".