31121551440405 has 48 divisors (see below), whose sum is σ = 54219224807280. Its totient is φ = 16513661251584.

The previous prime is 31121551440367. The next prime is 31121551440433. The reversal of 31121551440405 is 50404415512113.

31121551440405 is a `hidden beast` number, since 3 + 1 + 1 + 21 + 551 + 4 + 40 + 40 + 5 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 10477450398321 + 20644101042084 = 3236889^2 + 4543578^2 .

It is not a de Polignac number, because 31121551440405 - 2¹⁷ = 31121551309333 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31121551440405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6534031 + ... + 10243859.

It is an arithmetic number, because the mean of its divisors is an integer number (1129567183485).

Almost surely, 2^{31121551440405} is an apocalyptic number.

It is an amenable number.

31121551440405 is a deficient number, since it is larger than the sum of its proper divisors (23097673366875).

31121551440405 is a wasteful number, since it uses less digits than its factorization.

31121551440405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3710790 (or 3710787 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

Adding to 31121551440405 its reverse (50404415512113), we get a palindrome (81525966952518).

The spelling of 31121551440405 in words is "thirty-one trillion, one hundred twenty-one billion, five hundred fifty-one million, four hundred forty thousand, four hundred five".