64688639 has 2 divisors, whose sum is σ = 64688640. Its totient is φ = 64688638.

The previous prime is 64688633. The next prime is 64688651. The reversal of 64688639 is 93688646.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64688639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64688633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32344319 + 32344320.

It is an arithmetic number, because the mean of its divisors is an integer number (32344320).

Almost surely, 2^64688639 is an apocalyptic number.

64688639 is a deficient number, since it is larger than the sum of its proper divisors (1).

64688639 is an equidigital number, since it uses as much as digits as its factorization.

64688639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1492992, while the sum is 50.

The square root of 64688639 is about 8042.9247789595. The cubic root of 64688639 is about 401.4295494678.

The spelling of 64688639 in words is "sixty-four million, six hundred eighty-eight thousand, six hundred thirty-nine".