31881005 has 24 divisors (see below), whose sum is σ = 42887880. Its totient is φ = 22713600.

The previous prime is 31880987. The next prime is 31881011. The reversal of 31881005 is 50018813.

It can be written as a sum of positive squares in 12 ways, for example, as 28015849 + 3865156 = 5293^2 + 1966^2 .

It is not a de Polignac number, because 31881005 - 2⁶ = 31880941 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23855 + ... + 25155.

It is an arithmetic number, because the mean of its divisors is an integer number (1786995).

Almost surely, 2^31881005 is an apocalyptic number.

It is an amenable number.

31881005 is a deficient number, since it is larger than the sum of its proper divisors (11006875).

31881005 is a wasteful number, since it uses less digits than its factorization.

31881005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361 (or 1348 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 31881005 is about 5646.3266820119. The cubic root of 31881005 is about 317.0861949528.

Adding to 31881005 its reverse (50018813), we get a palindrome (81899818).

The spelling of 31881005 in words is "thirty-one million, eight hundred eighty-one thousand, five".