72781749 has 6 divisors (see below), whose sum is σ = 105129206. Its totient is φ = 48521160.

The previous prime is 72781747. The next prime is 72781763. The reversal of 72781749 is 94718727.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 49914225 + 22867524 = 7065^2 + 4782^2 .

It is not a de Polignac number, because 72781749 - 2¹ = 72781747 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 (72781747) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4043422 + ... + 4043439.

Almost surely, 2^72781749 is an apocalyptic number.

It is an amenable number.

72781749 is a deficient number, since it is larger than the sum of its proper divisors (32347457).

72781749 is a wasteful number, since it uses less digits than its factorization.

72781749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8086867 (or 8086864 counting only the distinct ones).

The product of its digits is 197568, while the sum is 45.

The square root of 72781749 is about 8531.2220109431. Note that the first 3 decimals coincide. The cubic root of 72781749 is about 417.5169993198.

The spelling of 72781749 in words is "seventy-two million, seven hundred eighty-one thousand, seven hundred forty-nine".