78742447 has 4 divisors (see below), whose sum is σ = 89991376. Its totient is φ = 67493520.

The previous prime is 78742439. The next prime is 78742451. The reversal of 78742447 is 74424787.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74424787 = 43 ⋅1730809.

It is a cyclic number.

It is not a de Polignac number, because 78742447 - 2³ = 78742439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78742747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5624454 + ... + 5624467.

It is an arithmetic number, because the mean of its divisors is an integer number (22497844).

Almost surely, 2^78742447 is an apocalyptic number.

78742447 is a deficient number, since it is larger than the sum of its proper divisors (11248929).

78742447 is a wasteful number, since it uses less digits than its factorization.

78742447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11248928.

The product of its digits is 351232, while the sum is 43.

The square root of 78742447 is about 8873.6941011058. The cubic root of 78742447 is about 428.6172401875.

It can be divided in two parts, 787 and 42447, that added together give a palindrome (43234).

The spelling of 78742447 in words is "seventy-eight million, seven hundred forty-two thousand, four hundred forty-seven".