261531403 has 8 divisors (see below), whose sum is σ = 298999008. Its totient is φ = 224090304.

The previous prime is 261531397. The next prime is 261531427. The reversal of 261531403 is 304135162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261531403 - 2⁹ = 261530891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261531443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23925 + ... + 33097.

It is an arithmetic number, because the mean of its divisors is an integer number (37374876).

Almost surely, 2^261531403 is an apocalyptic number.

261531403 is a deficient number, since it is larger than the sum of its proper divisors (37467605).

261531403 is an equidigital number, since it uses as much as digits as its factorization.

261531403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13253.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 261531403 is about 16171.9325684966. The cubic root of 261531403 is about 639.5010784445.

Adding to 261531403 its reverse (304135162), we get a palindrome (565666565).

It can be divided in two parts, 26153 and 1403, that added together give a square (27556 = 166²).

The spelling of 261531403 in words is "two hundred sixty-one million, five hundred thirty-one thousand, four hundred three".