65651581 has 2 divisors, whose sum is σ = 65651582. Its totient is φ = 65651580.

The previous prime is 65651561. The next prime is 65651587. The reversal of 65651581 is 18515656.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63059481 + 2592100 = 7941^2 + 1610^2 .

It is a cyclic number.

It is not a de Polignac number, because 65651581 - 2¹⁷ = 65520509 is a prime.

It is a super-2 number, since 2×65651581² = 8620260175599122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 65651581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65651587) 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, 32825790 + 32825791.

It is an arithmetic number, because the mean of its divisors is an integer number (32825791).

Almost surely, 2^65651581 is an apocalyptic number.

It is an amenable number.

65651581 is a deficient number, since it is larger than the sum of its proper divisors (1).

65651581 is an equidigital number, since it uses as much as digits as its factorization.

65651581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36000, while the sum is 37.

The square root of 65651581 is about 8102.5663218514. The cubic root of 65651581 is about 403.4116132621.

The spelling of 65651581 in words is "sixty-five million, six hundred fifty-one thousand, five hundred eighty-one".