31617781481 has 32 divisors (see below), whose sum is σ = 37381841280. Its totient is φ = 26364096000.

The previous prime is 31617781477. The next prime is 31617781501. The reversal of 31617781481 is 18418771613.

It is a happy number.

It is not a de Polignac number, because 31617781481 - 2² = 31617781477 is a prime.

It is a super-2 number, since 2×31617781481² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31617781471) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17554781 + ... + 17556581.

It is an arithmetic number, because the mean of its divisors is an integer number (1168182540).

Almost surely, 2^31617781481 is an apocalyptic number.

It is an amenable number.

31617781481 is a deficient number, since it is larger than the sum of its proper divisors (5764059799).

31617781481 is a wasteful number, since it uses less digits than its factorization.

31617781481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2537.

The product of its digits is 225792, while the sum is 47.

The spelling of 31617781481 in words is "thirty-one billion, six hundred seventeen million, seven hundred eighty-one thousand, four hundred eighty-one".