31821644065 has 4 divisors (see below), whose sum is σ = 38185972884. Its totient is φ = 25457315248.

The previous prime is 31821644039. The next prime is 31821644077. The reversal of 31821644065 is 56044612813.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56044612813 = 7 ⋅8006373259.

It can be written as a sum of positive squares in 2 ways, for example, as 4521352081 + 27300291984 = 67241^2 + 165228^2 .

It is a cyclic number.

It is not a de Polignac number, because 31821644065 - 2²⁹ = 31284773153 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3182164402 + ... + 3182164411.

It is an arithmetic number, because the mean of its divisors is an integer number (9546493221).

Almost surely, 2^31821644065 is an apocalyptic number.

It is an amenable number.

31821644065 is a deficient number, since it is larger than the sum of its proper divisors (6364328819).

31821644065 is an equidigital number, since it uses as much as digits as its factorization.

31821644065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6364328818.

The product of its (nonzero) digits is 138240, while the sum is 40.

The spelling of 31821644065 in words is "thirty-one billion, eight hundred twenty-one million, six hundred forty-four thousand, sixty-five".