78720100 has 36 divisors (see below), whose sum is σ = 174804784. Its totient is φ = 30754080.

The previous prime is 78720079. The next prime is 78720151. The reversal of 78720100 is 102787.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 4854 + ... + 13453.

Almost surely, 2^78720100 is an apocalyptic number.

It is an amenable number.

78720100 is an abundant number, since it is smaller than the sum of its proper divisors (96084684).

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

78720100 is a wasteful number, since it uses less digits than its factorization.

78720100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18364 (or 18357 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 78720100 is about 8872.4348405610. The cubic root of 78720100 is about 428.5766893534.

Adding to 78720100 its reverse (102787), we get a palindrome (78822887).

The spelling of 78720100 in words is "seventy-eight million, seven hundred twenty thousand, one hundred".