31478081 has 2 divisors, whose sum is σ = 31478082. Its totient is φ = 31478080.

The previous prime is 31478077. The next prime is 31478089. The reversal of 31478081 is 18087413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31181056 + 297025 = 5584^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 31478081 - 2² = 31478077 is a prime.

It is a super-2 number, since 2×31478081² = 1981739166885122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_1943582 and since 31478081 and 1943582 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (31478089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15739040 + 15739041.

It is an arithmetic number, because the mean of its divisors is an integer number (15739041).

Almost surely, 2^31478081 is an apocalyptic number.

It is an amenable number.

31478081 is a deficient number, since it is larger than the sum of its proper divisors (1).

31478081 is an equidigital number, since it uses as much as digits as its factorization.

31478081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 31478081 is about 5610.5330406299. The cubic root of 31478081 is about 315.7447098240.

The spelling of 31478081 in words is "thirty-one million, four hundred seventy-eight thousand, eighty-one".