647021 has 8 divisors (see below), whose sum is σ = 680064. Its totient is φ = 614880.

The previous prime is 647011. The next prime is 647033. The reversal of 647021 is 120746.

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 647021 - 2⁶ = 646957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 646984 and 647002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647011) 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, 1580 + ... + 1946.

It is an arithmetic number, because the mean of its divisors is an integer number (85008).

2⁶⁴⁷⁰²¹ is an apocalyptic number.

It is an amenable number.

647021 is a deficient number, since it is larger than the sum of its proper divisors (33043).

647021 is a wasteful number, since it uses less digits than its factorization.

647021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 647021 is about 804.3761557878. The cubic root of 647021 is about 86.4913731693.

Adding to 647021 its reverse (120746), we get a palindrome (767767).

The spelling of 647021 in words is "six hundred forty-seven thousand, twenty-one".