78720489 has 12 divisors (see below), whose sum is σ = 120396276. Its totient is φ = 49393152.

The previous prime is 78720479. The next prime is 78720493. The reversal of 78720489 is 98402787.

It can be written as a sum of positive squares in 2 ways, for example, as 68608089 + 10112400 = 8283^2 + 3180^2 .

It is not a de Polignac number, because 78720489 - 2⁵ = 78720457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78720409) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 257104 + ... + 257409.

It is an arithmetic number, because the mean of its divisors is an integer number (10033023).

Almost surely, 2^78720489 is an apocalyptic number.

It is an amenable number.

78720489 is a deficient number, since it is larger than the sum of its proper divisors (41675787).

78720489 is a wasteful number, since it uses less digits than its factorization.

78720489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514536 (or 514533 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The square root of 78720489 is about 8872.4567623629. The cubic root of 78720489 is about 428.5773952979.

The spelling of 78720489 in words is "seventy-eight million, seven hundred twenty thousand, four hundred eighty-nine".