31641981989 has 4 divisors (see below), whose sum is σ = 31658370240. Its totient is φ = 31625593740.

The previous prime is 31641981979. The next prime is 31641981991. The reversal of 31641981989 is 98918914613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98918914613 = 16607 ⋅5956459.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31641981989 is a prime.

It is a super-2 number, since 2×31641981989² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31641981979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8191229 + ... + 8195090.

It is an arithmetic number, because the mean of its divisors is an integer number (7914592560).

Almost surely, 2^31641981989 is an apocalyptic number.

It is an amenable number.

31641981989 is a deficient number, since it is larger than the sum of its proper divisors (16388251).

31641981989 is a wasteful number, since it uses less digits than its factorization.

31641981989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16388250.

The product of its digits is 3359232, while the sum is 59.

The spelling of 31641981989 in words is "thirty-one billion, six hundred forty-one million, nine hundred eighty-one thousand, nine hundred eighty-nine".