420647 has 4 divisors (see below), whose sum is σ = 438960. Its totient is φ = 402336.

The previous prime is 420613. The next prime is 420671. The reversal of 420647 is 746024.

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

It is a cyclic number.

It is not a de Polignac number, because 420647 - 2¹⁰ = 419623 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 18289 = 420647 / (4 + 2 + 0 + 6 + 4 + 7).

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 420647.

It is not an unprimeable number, because it can be changed into a prime (420677) 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, 9122 + ... + 9167.

It is an arithmetic number, because the mean of its divisors is an integer number (109740).

2⁴²⁰⁶⁴⁷ is an apocalyptic number.

420647 is a deficient number, since it is larger than the sum of its proper divisors (18313).

420647 is a wasteful number, since it uses less digits than its factorization.

420647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18312.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 420647 is about 648.5730490855. The cubic root of 420647 is about 74.9271589082.

The spelling of 420647 in words is "four hundred twenty thousand, six hundred forty-seven".