642775 has 12 divisors (see below), whose sum is σ = 911152. Its totient is φ = 440640.

The previous prime is 642769. The next prime is 642779. The reversal of 642775 is 577246.

642775 = T₂₉₆ + T₂₉₇ + ... + T₃₀₉.

It is not a de Polignac number, because 642775 - 2¹¹ = 640727 is a prime.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

642775 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642779) 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 in 11 ways as a sum of consecutive naturals, for example, 1662 + ... + 2011.

2⁶⁴²⁷⁷⁵ is an apocalyptic number.

642775 is a deficient number, since it is larger than the sum of its proper divisors (268377).

642775 is a wasteful number, since it uses less digits than its factorization.

642775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3690 (or 3685 counting only the distinct ones).

The product of its digits is 11760, while the sum is 31.

The square root of 642775 is about 801.7324990294. The cubic root of 642775 is about 86.3017612708.

The spelling of 642775 in words is "six hundred forty-two thousand, seven hundred seventy-five".