31389431 has 4 divisors (see below), whose sum is σ = 32237832. Its totient is φ = 30541032.

The previous prime is 31389419. The next prime is 31389437. The reversal of 31389431 is 13498313.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13498313 = 3011 ⋅4483.

It is a cyclic number.

It is not a de Polignac number, because 31389431 - 2⁶ = 31389367 is a prime.

It is a super-2 number, since 2×31389431² = 1970592757007522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31389437) 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, 424145 + ... + 424218.

It is an arithmetic number, because the mean of its divisors is an integer number (8059458).

Almost surely, 2^31389431 is an apocalyptic number.

31389431 is a deficient number, since it is larger than the sum of its proper divisors (848401).

31389431 is an equidigital number, since it uses as much as digits as its factorization.

31389431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848400.

The product of its digits is 7776, while the sum is 32.

The square root of 31389431 is about 5602.6271516138. The cubic root of 31389431 is about 315.4480262788.

The spelling of 31389431 in words is "thirty-one million, three hundred eighty-nine thousand, four hundred thirty-one".