81616753 has 2 divisors, whose sum is σ = 81616754. Its totient is φ = 81616752.

The previous prime is 81616747. The next prime is 81616781. The reversal of 81616753 is 35761618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65480464 + 16136289 = 8092^2 + 4017^2 .

It is a cyclic number.

It is not a de Polignac number, because 81616753 - 2¹³ = 81608561 is a prime.

It is a super-2 number, since 2×81616753² = 13322588740526018, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81616793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40808376 + 40808377.

It is an arithmetic number, because the mean of its divisors is an integer number (40808377).

Almost surely, 2^81616753 is an apocalyptic number.

It is an amenable number.

81616753 is a deficient number, since it is larger than the sum of its proper divisors (1).

81616753 is an equidigital number, since it uses as much as digits as its factorization.

81616753 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 37.

The square root of 81616753 is about 9034.1990790551. The cubic root of 81616753 is about 433.7702582537.

It can be divided in two parts, 81616 and 753, that added together give a square (82369 = 287²).

The spelling of 81616753 in words is "eighty-one million, six hundred sixteen thousand, seven hundred fifty-three".