72085781 has 2 divisors, whose sum is σ = 72085782. Its totient is φ = 72085780.

The previous prime is 72085771. The next prime is 72085789. The reversal of 72085781 is 18758027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58828900 + 13256881 = 7670^2 + 3641^2 .

It is a cyclic number.

It is not a de Polignac number, because 72085781 - 2¹⁰ = 72084757 is a prime.

It is a super-2 number, since 2×72085781² = 10392719644759922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72085789) 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 as a sum of consecutive naturals, namely, 36042890 + 36042891.

It is an arithmetic number, because the mean of its divisors is an integer number (36042891).

Almost surely, 2^72085781 is an apocalyptic number.

It is an amenable number.

72085781 is a deficient number, since it is larger than the sum of its proper divisors (1).

72085781 is an equidigital number, since it uses as much as digits as its factorization.

72085781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 72085781 is about 8490.3345634904. The cubic root of 72085781 is about 416.1819135511.

The spelling of 72085781 in words is "seventy-two million, eighty-five thousand, seven hundred eighty-one".