647665663 has 4 divisors (see below), whose sum is σ = 651791080. Its totient is φ = 643540248.

The previous prime is 647665633. The next prime is 647665693. The reversal of 647665663 is 366566746.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (647665633) and next prime (647665693).

It is a cyclic number.

It is not a de Polignac number, because 647665663 - 2¹³ = 647657471 is a prime.

It is a super-2 number, since 2×647665663² = 838941622058459138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647665633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2062473 + ... + 2062786.

It is an arithmetic number, because the mean of its divisors is an integer number (162947770).

Almost surely, 2^647665663 is an apocalyptic number.

647665663 is a deficient number, since it is larger than the sum of its proper divisors (4125417).

647665663 is a wasteful number, since it uses less digits than its factorization.

647665663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4125416.

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

The square root of 647665663 is about 25449.2762765466. The cubic root of 647665663 is about 865.2008902250.

The spelling of 647665663 in words is "six hundred forty-seven million, six hundred sixty-five thousand, six hundred sixty-three".