72781073 has 4 divisors (see below), whose sum is σ = 73778148. Its totient is φ = 71784000.

The previous prime is 72781067. The next prime is 72781103. The reversal of 72781073 is 37018727.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37018727 = 739 ⋅50093.

It can be written as a sum of positive squares in 2 ways, for example, as 39337984 + 33443089 = 6272^2 + 5783^2 .

It is a cyclic number.

It is not a de Polignac number, because 72781073 - 2⁴ = 72781057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72781003) 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 3 ways as a sum of consecutive naturals, for example, 498428 + ... + 498573.

It is an arithmetic number, because the mean of its divisors is an integer number (18444537).

Almost surely, 2^72781073 is an apocalyptic number.

72781073 is a gapful number since it is divisible by the number (73) formed by its first and last digit.

It is an amenable number.

72781073 is a deficient number, since it is larger than the sum of its proper divisors (997075).

72781073 is an equidigital number, since it uses as much as digits as its factorization.

72781073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 997074.

The product of its (nonzero) digits is 16464, while the sum is 35.

The square root of 72781073 is about 8531.1823916735. The cubic root of 72781073 is about 417.5157066772.

The spelling of 72781073 in words is "seventy-two million, seven hundred eighty-one thousand, seventy-three".