78488991 has 24 divisors (see below), whose sum is σ = 130515840. Its totient is φ = 44523216.

The previous prime is 78488989. The next prime is 78489001. The reversal of 78488991 is 19988487.

78488991 is a `hidden beast` number, since 78 + 488 + 9 + 91 = 666.

It is not a de Polignac number, because 78488991 - 2¹ = 78488989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78488911) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4276 + ... + 13238.

It is an arithmetic number, because the mean of its divisors is an integer number (5438160).

Almost surely, 2^78488991 is an apocalyptic number.

78488991 is a deficient number, since it is larger than the sum of its proper divisors (52026849).

78488991 is a wasteful number, since it uses less digits than its factorization.

78488991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9115 (or 9112 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 54.

The square root of 78488991 is about 8859.4012777388. The cubic root of 78488991 is about 428.1568685035.

The spelling of 78488991 in words is "seventy-eight million, four hundred eighty-eight thousand, nine hundred ninety-one".