647627021 has 8 divisors (see below), whose sum is σ = 681354744. Its totient is φ = 614753280.

The previous prime is 647626963. The next prime is 647627081. The reversal of 647627021 is 120726746.

It can be written as a sum of positive squares in 4 ways, for example, as 18369796 + 629257225 = 4286^2 + 25085^2 .

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 647627021 - 2²² = 643432717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647627081) 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 7 ways as a sum of consecutive naturals, for example, 211940 + ... + 214973.

It is an arithmetic number, because the mean of its divisors is an integer number (85169343).

Almost surely, 2^647627021 is an apocalyptic number.

It is an amenable number.

647627021 is a deficient number, since it is larger than the sum of its proper divisors (33727723).

647627021 is a wasteful number, since it uses less digits than its factorization.

647627021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426991.

The product of its (nonzero) digits is 28224, while the sum is 35.

The square root of 647627021 is about 25448.5170687803. The cubic root of 647627021 is about 865.1836829118.

The spelling of 647627021 in words is "six hundred forty-seven million, six hundred twenty-seven thousand, twenty-one".