64639847 has 2 divisors, whose sum is σ = 64639848. Its totient is φ = 64639846.

The previous prime is 64639823. The next prime is 64639849. The reversal of 64639847 is 74893646.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64639847 is a prime.

Together with 64639849, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64639849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32319923 + 32319924.

It is an arithmetic number, because the mean of its divisors is an integer number (32319924).

Almost surely, 2^64639847 is an apocalyptic number.

64639847 is a deficient number, since it is larger than the sum of its proper divisors (1).

64639847 is an equidigital number, since it uses as much as digits as its factorization.

64639847 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 47.

The square root of 64639847 is about 8039.8909818480. The cubic root of 64639847 is about 401.3285967740.

The spelling of 64639847 in words is "sixty-four million, six hundred thirty-nine thousand, eight hundred forty-seven".