72778617 has 6 divisors (see below), whose sum is σ = 105124682. Its totient is φ = 48519072.

The previous prime is 72778613. The next prime is 72778619. The reversal of 72778617 is 71687727.

It is a happy number.

72778617 is a `hidden beast` number, since 7 + 27 + 7 + 8 + 617 = 666.

It can be written as a sum of positive squares in only one way, i.e., 53934336 + 18844281 = 7344^2 + 4341^2 .

It is not a de Polignac number, because 72778617 - 2² = 72778613 is a prime.

It is a super-3 number, since 3×72778617³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72778613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4043248 + ... + 4043265.

Almost surely, 2^72778617 is an apocalyptic number.

It is an amenable number.

72778617 is a deficient number, since it is larger than the sum of its proper divisors (32346065).

72778617 is a wasteful number, since it uses less digits than its factorization.

72778617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8086519 (or 8086516 counting only the distinct ones).

The product of its digits is 230496, while the sum is 45.

The square root of 72778617 is about 8531.0384479265. The cubic root of 72778617 is about 417.5110102634.

The spelling of 72778617 in words is "seventy-two million, seven hundred seventy-eight thousand, six hundred seventeen".