647441257 has 4 divisors (see below), whose sum is σ = 647862400. Its totient is φ = 647020116.

The previous prime is 647441227. The next prime is 647441273. The reversal of 647441257 is 752144746.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 647441257 - 2¹⁹ = 646916969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647441227) 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, 208257 + ... + 211342.

It is an arithmetic number, because the mean of its divisors is an integer number (161965600).

Almost surely, 2^647441257 is an apocalyptic number.

It is an amenable number.

647441257 is a deficient number, since it is larger than the sum of its proper divisors (421143).

647441257 is a wasteful number, since it uses less digits than its factorization.

647441257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421142.

The product of its digits is 188160, while the sum is 40.

The square root of 647441257 is about 25444.8670069230. The cubic root of 647441257 is about 865.1009524997.

The spelling of 647441257 in words is "six hundred forty-seven million, four hundred forty-one thousand, two hundred fifty-seven".