72779447 has 4 divisors (see below), whose sum is σ = 78377880. Its totient is φ = 67181016.

The previous prime is 72779437. The next prime is 72779449. The reversal of 72779447 is 74497727.

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: 74497727 = 19 ⋅3920933.

It is a cyclic number.

It is not a de Polignac number, because 72779447 - 2¹⁶ = 72713911 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 (72779449) 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, 2799197 + ... + 2799222.

It is an arithmetic number, because the mean of its divisors is an integer number (19594470).

Almost surely, 2^72779447 is an apocalyptic number.

72779447 is a deficient number, since it is larger than the sum of its proper divisors (5598433).

72779447 is a wasteful number, since it uses less digits than its factorization.

72779447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5598432.

The product of its digits is 691488, while the sum is 47.

The square root of 72779447 is about 8531.0870936827. The cubic root of 72779447 is about 417.5125974183.

The spelling of 72779447 in words is "seventy-two million, seven hundred seventy-nine thousand, four hundred forty-seven".