31443431 has 4 divisors (see below), whose sum is σ = 31592664. Its totient is φ = 31294200.

The previous prime is 31443409. The next prime is 31443443. The reversal of 31443431 is 13434413.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13434413 = 379 ⋅35447.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31443431 is a prime.

It is a super-2 number, since 2×31443431² = 1977378706103522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31443397 and 31443406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31443481) 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, 74300 + ... + 74721.

It is an arithmetic number, because the mean of its divisors is an integer number (7898166).

Almost surely, 2^31443431 is an apocalyptic number.

31443431 is a deficient number, since it is larger than the sum of its proper divisors (149233).

31443431 is a wasteful number, since it uses less digits than its factorization.

31443431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149232.

The product of its digits is 1728, while the sum is 23.

The square root of 31443431 is about 5607.4442484968. Note that the first 3 decimals coincide. The cubic root of 31443431 is about 315.6288136127.

Adding to 31443431 its reverse (13434413), we get a palindrome (44877844).

The spelling of 31443431 in words is "thirty-one million, four hundred forty-three thousand, four hundred thirty-one".