78621816 has 64 divisors (see below), whose sum is σ = 241920000. Its totient is φ = 20734848.

The previous prime is 78621811. The next prime is 78621817. The reversal of 78621816 is 61812687.

It is a super-2 number, since 2×78621816² = 12362779902275712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78621811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15816 + ... + 20183.

It is an arithmetic number, because the mean of its divisors is an integer number (3780000).

Almost surely, 2^78621816 is an apocalyptic number.

It is an amenable number.

78621816 is an abundant number, since it is smaller than the sum of its proper divisors (163298184).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78621816 is a wasteful number, since it uses less digits than its factorization.

78621816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36028 (or 36024 counting only the distinct ones).

The product of its digits is 32256, while the sum is 39.

The square root of 78621816 is about 8866.8943830408. The cubic root of 78621816 is about 428.3982521914.

The spelling of 78621816 in words is "seventy-eight million, six hundred twenty-one thousand, eight hundred sixteen".