65686639 has 2 divisors, whose sum is σ = 65686640. Its totient is φ = 65686638.

The previous prime is 65686609. The next prime is 65686651. The reversal of 65686639 is 93668656.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65686639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 65686592 and 65686601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65686609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32843319 + 32843320.

It is an arithmetic number, because the mean of its divisors is an integer number (32843320).

Almost surely, 2^65686639 is an apocalyptic number.

65686639 is a deficient number, since it is larger than the sum of its proper divisors (1).

65686639 is an equidigital number, since it uses as much as digits as its factorization.

65686639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1399680, while the sum is 49.

The square root of 65686639 is about 8104.7294217636. The cubic root of 65686639 is about 403.4834078655.

The spelling of 65686639 in words is "sixty-five million, six hundred eighty-six thousand, six hundred thirty-nine".