72780013 has 4 divisors (see below), whose sum is σ = 76610560. Its totient is φ = 68949468.

The previous prime is 72779969. The next prime is 72780047. The reversal of 72780013 is 31008727.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31008727 = 167 ⋅185681.

It is a cyclic number.

It is not a de Polignac number, because 72780013 - 2⁹ = 72779501 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 (72781013) 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 3 ways as a sum of consecutive naturals, for example, 1915245 + ... + 1915282.

It is an arithmetic number, because the mean of its divisors is an integer number (19152640).

Almost surely, 2^72780013 is an apocalyptic number.

It is an amenable number.

72780013 is a deficient number, since it is larger than the sum of its proper divisors (3830547).

72780013 is a wasteful number, since it uses less digits than its factorization.

72780013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3830546.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 72780013 is about 8531.1202664128. The cubic root of 72780013 is about 417.5136797363.

The spelling of 72780013 in words is "seventy-two million, seven hundred eighty thousand, thirteen".