261320403 has 4 divisors (see below), whose sum is σ = 348427208. Its totient is φ = 174213600.

The previous prime is 261320393. The next prime is 261320419. The reversal of 261320403 is 304023162.

It is a happy number.

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

It is not a de Polignac number, because 261320403 - 2¹³ = 261312211 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261320403.

It is not an unprimeable number, because it can be changed into a prime (261320453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43553398 + ... + 43553403.

It is an arithmetic number, because the mean of its divisors is an integer number (87106802).

Almost surely, 2^261320403 is an apocalyptic number.

261320403 is a deficient number, since it is larger than the sum of its proper divisors (87106805).

261320403 is an equidigital number, since it uses as much as digits as its factorization.

261320403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87106804.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 261320403 is about 16165.4076038929. The cubic root of 261320403 is about 639.3290518986.

Adding to 261320403 its reverse (304023162), we get a palindrome (565343565).

The spelling of 261320403 in words is "two hundred sixty-one million, three hundred twenty thousand, four hundred three".