31440423 has 16 divisors (see below), whose sum is σ = 47990016. Its totient is φ = 17935680.

The previous prime is 31440419. The next prime is 31440427. The reversal of 31440423 is 32404413.

It is an interprime number because it is at equal distance from previous prime (31440419) and next prime (31440427).

It is not a de Polignac number, because 31440423 - 2² = 31440419 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 31440423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31440427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19228 + ... + 20798.

It is an arithmetic number, because the mean of its divisors is an integer number (2999376).

Almost surely, 2^31440423 is an apocalyptic number.

31440423 is a deficient number, since it is larger than the sum of its proper divisors (16549593).

31440423 is a wasteful number, since it uses less digits than its factorization.

31440423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2534.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 31440423 is about 5607.1760271994. The cubic root of 31440423 is about 315.6187485348.

Adding to 31440423 its reverse (32404413), we get a palindrome (63844836).

The spelling of 31440423 in words is "thirty-one million, four hundred forty thousand, four hundred twenty-three".