78213234477665 has 64 divisors (see below), whose sum is σ = 109140800827392. Its totient is φ = 52695409939200.

The previous prime is 78213234477661. The next prime is 78213234477743. The reversal of 78213234477665 is 56677443231287.

It is a happy number.

It is not a de Polignac number, because 78213234477665 - 2² = 78213234477661 is a prime.

It is a super-2 number, since 2×78213234477665² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78213234477661) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 11105098634 + ... + 11105105676.

It is an arithmetic number, because the mean of its divisors is an integer number (1705325012928).

Almost surely, 2^{78213234477665} is an apocalyptic number.

It is an amenable number.

78213234477665 is a deficient number, since it is larger than the sum of its proper divisors (30927566349727).

78213234477665 is a wasteful number, since it uses less digits than its factorization.

78213234477665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12030.

The product of its digits is 284497920, while the sum is 65.

The spelling of 78213234477665 in words is "seventy-eight trillion, two hundred thirteen billion, two hundred thirty-four million, four hundred seventy-seven thousand, six hundred sixty-five".