642547 has 2 divisors, whose sum is σ = 642548. Its totient is φ = 642546.

The previous prime is 642533. The next prime is 642557. The reversal of 642547 is 745246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642547 - 2⁷ = 642419 is a prime.

It is not a weakly prime, because it can be changed into another prime (642517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321273 + 321274.

It is an arithmetic number, because the mean of its divisors is an integer number (321274).

2⁶⁴²⁵⁴⁷ is an apocalyptic number.

642547 is a deficient number, since it is larger than the sum of its proper divisors (1).

642547 is an equidigital number, since it uses as much as digits as its factorization.

642547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 28.

The square root of 642547 is about 801.5902943524. The cubic root of 642547 is about 86.2915559742.

It can be divided in two parts, 64254 and 7, that added together give a triangular number (64261 = T₃₅₈).

The spelling of 642547 in words is "six hundred forty-two thousand, five hundred forty-seven".