65699681 has 2 divisors, whose sum is σ = 65699682. Its totient is φ = 65699680.

The previous prime is 65699677. The next prime is 65699687. The reversal of 65699681 is 18699656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44622400 + 21077281 = 6680^2 + 4591^2 .

It is a cyclic number.

It is not a de Polignac number, because 65699681 - 2² = 65699677 is a prime.

It is a super-2 number, since 2×65699681² = 8632896167003522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (65699687) 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, 32849840 + 32849841.

It is an arithmetic number, because the mean of its divisors is an integer number (32849841).

Almost surely, 2^65699681 is an apocalyptic number.

It is an amenable number.

65699681 is a deficient number, since it is larger than the sum of its proper divisors (1).

65699681 is an equidigital number, since it uses as much as digits as its factorization.

65699681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 50.

The square root of 65699681 is about 8105.5339737737. The cubic root of 65699681 is about 403.5101098070.

The spelling of 65699681 in words is "sixty-five million, six hundred ninety-nine thousand, six hundred eighty-one".