72071761 has 2 divisors, whose sum is σ = 72071762. Its totient is φ = 72071760.

The previous prime is 72071729. The next prime is 72071767. The reversal of 72071761 is 16717027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71927361 + 144400 = 8481^2 + 380^2 .

It is an emirp because it is prime and its reverse (16717027) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72071761 - 2⁵ = 72071729 is a prime.

It is a super-2 number, since 2×72071761² = 10388677467282242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72071767) 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, 36035880 + 36035881.

It is an arithmetic number, because the mean of its divisors is an integer number (36035881).

Almost surely, 2^72071761 is an apocalyptic number.

It is an amenable number.

72071761 is a deficient number, since it is larger than the sum of its proper divisors (1).

72071761 is an equidigital number, since it uses as much as digits as its factorization.

72071761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4116, while the sum is 31.

The square root of 72071761 is about 8489.5088786101. The cubic root of 72071761 is about 416.1549306581.

Adding to 72071761 its reverse (16717027), we get a palindrome (88788788).

The spelling of 72071761 in words is "seventy-two million, seventy-one thousand, seven hundred sixty-one".