72777665 has 16 divisors (see below), whose sum is σ = 90311760. Its totient is φ = 56263680.

The previous prime is 72777659. The next prime is 72777673. The reversal of 72777665 is 56677727.

It can be written as a sum of positive squares in 8 ways, for example, as 204304 + 72573361 = 452^2 + 8519^2 .

It is not a de Polignac number, because 72777665 - 2²⁴ = 56000449 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20717 + ... + 23973.

It is an arithmetic number, because the mean of its divisors is an integer number (5644485).

Almost surely, 2^72777665 is an apocalyptic number.

It is an amenable number.

72777665 is a deficient number, since it is larger than the sum of its proper divisors (17534095).

72777665 is a wasteful number, since it uses less digits than its factorization.

72777665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3412.

The product of its digits is 864360, while the sum is 47.

The square root of 72777665 is about 8530.9826514886. The cubic root of 72777665 is about 417.5091898009.

The spelling of 72777665 in words is "seventy-two million, seven hundred seventy-seven thousand, six hundred sixty-five".