31431261 has 4 divisors (see below), whose sum is σ = 41908352. Its totient is φ = 20954172.

The previous prime is 31431251. The next prime is 31431269. The reversal of 31431261 is 16213413.

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 not a de Polignac number, because 31431261 - 2⁵ = 31431229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31431269) 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, 5238541 + ... + 5238546.

It is an arithmetic number, because the mean of its divisors is an integer number (10477088).

Almost surely, 2^31431261 is an apocalyptic number.

It is an amenable number.

31431261 is a deficient number, since it is larger than the sum of its proper divisors (10477091).

31431261 is a wasteful number, since it uses less digits than its factorization.

31431261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10477090.

The product of its digits is 432, while the sum is 21.

The square root of 31431261 is about 5606.3589788739. The cubic root of 31431261 is about 315.5880875827.

Adding to 31431261 its reverse (16213413), we get a palindrome (47644674).

The spelling of 31431261 in words is "thirty-one million, four hundred thirty-one thousand, two hundred sixty-one".