31997743 has 4 divisors (see below), whose sum is σ = 32601528. Its totient is φ = 31393960.

The previous prime is 31997737. The next prime is 31997747. The reversal of 31997743 is 34779913.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34779913 = 7 ⋅4968559.

It is a cyclic number.

It is not a de Polignac number, because 31997743 - 2¹⁷ = 31866671 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31997743.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31997747) 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, 301813 + ... + 301918.

It is an arithmetic number, because the mean of its divisors is an integer number (8150382).

Almost surely, 2^31997743 is an apocalyptic number.

31997743 is a deficient number, since it is larger than the sum of its proper divisors (603785).

31997743 is an equidigital number, since it uses as much as digits as its factorization.

31997743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603784.

The product of its digits is 142884, while the sum is 43.

The square root of 31997743 is about 5656.6547534740. The cubic root of 31997743 is about 317.4727461261.

The spelling of 31997743 in words is "thirty-one million, nine hundred ninety-seven thousand, seven hundred forty-three".