431261561 has 4 divisors (see below), whose sum is σ = 431341824. Its totient is φ = 431181300.

The previous prime is 431261543. The next prime is 431261669. The reversal of 431261561 is 165162134.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 431261561 - 2²⁶ = 364152697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (431261531) 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, 31445 + ... + 43026.

It is an arithmetic number, because the mean of its divisors is an integer number (107835456).

Almost surely, 2^431261561 is an apocalyptic number.

It is an amenable number.

431261561 is a deficient number, since it is larger than the sum of its proper divisors (80263).

431261561 is an equidigital number, since it uses as much as digits as its factorization.

431261561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80262.

The product of its digits is 4320, while the sum is 29.

The square root of 431261561 is about 20766.8380115992. The cubic root of 431261561 is about 755.5216551887.

The spelling of 431261561 in words is "four hundred thirty-one million, two hundred sixty-one thousand, five hundred sixty-one".