78219720 has 96 divisors (see below), whose sum is σ = 269188920. Its totient is φ = 19630080.

The previous prime is 78219689. The next prime is 78219721. The reversal of 78219720 is 2791287.

It can be written as a sum of positive squares in 4 ways, for example, as 75377124 + 2842596 = 8682^2 + 1686^2 .

It is a super-2 number, since 2×78219720² = 12236649193756800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (78219721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 271 + ... + 12510.

Almost surely, 2^78219720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78219720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134594460).

78219720 is an abundant number, since it is smaller than the sum of its proper divisors (190969200).

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

78219720 is a wasteful number, since it uses less digits than its factorization.

78219720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12815 (or 12808 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 78219720 is about 8844.1913140773. The cubic root of 78219720 is about 427.6666837442. Note that the first 4 decimals are identical.

It can be divided in two parts, 782 and 19720, that added together give a palindrome (20502).

The spelling of 78219720 in words is "seventy-eight million, two hundred nineteen thousand, seven hundred twenty".