72779945 has 12 divisors (see below), whose sum is σ = 101595204. Its totient is φ = 49906080.

The previous prime is 72779921. The next prime is 72779947. The reversal of 72779945 is 54997727.

72779945 = 114² + 115² + ... + 603².

It can be written as a sum of positive squares in 2 ways, for example, as 57577744 + 15202201 = 7588^2 + 3899^2 .

It is not a de Polignac number, because 72779945 - 2¹⁶ = 72714409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 72779893 and 72779902.

It is not an unprimeable number, because it can be changed into a prime (72779947) by changing a digit.

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, 148286 + ... + 148775.

It is an arithmetic number, because the mean of its divisors is an integer number (8466267).

Almost surely, 2^72779945 is an apocalyptic number.

It is an amenable number.

72779945 is a deficient number, since it is larger than the sum of its proper divisors (28815259).

72779945 is a wasteful number, since it uses less digits than its factorization.

72779945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297080 (or 297073 counting only the distinct ones).

The product of its digits is 1111320, while the sum is 50.

The square root of 72779945 is about 8531.1162810033. The cubic root of 72779945 is about 417.5135497055.

The spelling of 72779945 in words is "seventy-two million, seven hundred seventy-nine thousand, nine hundred forty-five".