78195621 has 24 divisors (see below), whose sum is σ = 127670880. Its totient is φ = 42329952.

The previous prime is 78195587. The next prime is 78195641. The reversal of 78195621 is 12659187.

It is not a de Polignac number, because 78195621 - 2¹⁸ = 77933477 is a prime.

It is a super-2 number, since 2×78195621² = 12229110287151282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78195621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78195641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11206 + ... + 16791.

It is an arithmetic number, because the mean of its divisors is an integer number (5319620).

Almost surely, 2^78195621 is an apocalyptic number.

It is an amenable number.

78195621 is a deficient number, since it is larger than the sum of its proper divisors (49475259).

78195621 is a wasteful number, since it uses less digits than its factorization.

78195621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28033 (or 28026 counting only the distinct ones).

The product of its digits is 30240, while the sum is 39.

The square root of 78195621 is about 8842.8287894768. The cubic root of 78195621 is about 427.6227587679.

The spelling of 78195621 in words is "seventy-eight million, one hundred ninety-five thousand, six hundred twenty-one".