31517421305 has 8 divisors (see below), whose sum is σ = 37821897672. Its totient is φ = 25213275648.

The previous prime is 31517421263. The next prime is 31517421311. The reversal of 31517421305 is 50312471513.

It can be written as a sum of positive squares in 4 ways, for example, as 13046436841 + 18470984464 = 114221^2 + 135908^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31517421305 - 2⁸ = 31517421049 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 245219 + ... + 350951.

It is an arithmetic number, because the mean of its divisors is an integer number (4727737209).

Almost surely, 2^31517421305 is an apocalyptic number.

It is an amenable number.

31517421305 is a deficient number, since it is larger than the sum of its proper divisors (6304476367).

31517421305 is a wasteful number, since it uses less digits than its factorization.

31517421305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165355.

The product of its (nonzero) digits is 12600, while the sum is 32.

Adding to 31517421305 its reverse (50312471513), we get a palindrome (81829892818).

The spelling of 31517421305 in words is "thirty-one billion, five hundred seventeen million, four hundred twenty-one thousand, three hundred five".