647643457 has 4 divisors (see below), whose sum is σ = 669976020. Its totient is φ = 625310896.

The previous prime is 647643431. The next prime is 647643463. The reversal of 647643457 is 754346746.

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

It can be written as a sum of positive squares in 2 ways, for example, as 509134096 + 138509361 = 22564^2 + 11769^2 .

It is a cyclic number.

It is not a de Polignac number, because 647643457 - 2¹¹ = 647641409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647643467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11166238 + ... + 11166295.

It is an arithmetic number, because the mean of its divisors is an integer number (167494005).

Almost surely, 2^647643457 is an apocalyptic number.

It is an amenable number.

647643457 is a deficient number, since it is larger than the sum of its proper divisors (22332563).

647643457 is a wasteful number, since it uses less digits than its factorization.

647643457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22332562.

The product of its digits is 1693440, while the sum is 46.

The square root of 647643457 is about 25448.8399932099. The cubic root of 647643457 is about 865.1910019593.

The spelling of 647643457 in words is "six hundred forty-seven million, six hundred forty-three thousand, four hundred fifty-seven".