636665647 has 8 divisors (see below), whose sum is σ = 640681920. Its totient is φ = 632661120.

The previous prime is 636665573. The next prime is 636665663. The reversal of 636665647 is 746566636.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 636665647 - 2¹⁵ = 636632879 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 636665647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636666647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121963 + ... + 127075.

It is an arithmetic number, because the mean of its divisors is an integer number (80085240).

Almost surely, 2^636665647 is an apocalyptic number.

636665647 is a deficient number, since it is larger than the sum of its proper divisors (4016273).

636665647 is a wasteful number, since it uses less digits than its factorization.

636665647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5873.

The product of its digits is 3265920, while the sum is 49.

The square root of 636665647 is about 25232.2342847398. The cubic root of 636665647 is about 860.2746765484.

The spelling of 636665647 in words is "six hundred thirty-six million, six hundred sixty-five thousand, six hundred forty-seven".