261443603 has 4 divisors (see below), whose sum is σ = 261569448. Its totient is φ = 261317760.

The previous prime is 261443557. The next prime is 261443617. The reversal of 261443603 is 306344162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 306344162 = 2 ⋅153172081.

It is a cyclic number.

It is not a de Polignac number, because 261443603 - 2¹⁶ = 261378067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261443653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59753 + ... + 63978.

It is an arithmetic number, because the mean of its divisors is an integer number (65392362).

Almost surely, 2^261443603 is an apocalyptic number.

261443603 is a deficient number, since it is larger than the sum of its proper divisors (125845).

261443603 is a wasteful number, since it uses less digits than its factorization.

261443603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125844.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 261443603 is about 16169.2177609184. The cubic root of 261443603 is about 639.4295070787.

Adding to 261443603 its reverse (306344162), we get a palindrome (567787765).

The spelling of 261443603 in words is "two hundred sixty-one million, four hundred forty-three thousand, six hundred three".