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640231 is a prime number
BaseRepresentation
bin10011100010011100111
31012112020021
42130103213
5130441411
621420011
75304364
oct2342347
91175207
10640231
113a8019
1226a607
13195547
1412946b
15c9a71
hex9c4e7

640231 has 2 divisors, whose sum is σ = 640232. Its totient is φ = 640230.

The previous prime is 640229. The next prime is 640247. The reversal of 640231 is 132046.

It is an a-pointer prime, because the next prime (640247) can be obtained adding 640231 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640231 - 21 = 640229 is a prime.

It is a super-2 number, since 2×6402312 = 819791466722, which contains 22 as substring.

Together with 640229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640261) 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 as a sum of consecutive naturals, namely, 320115 + 320116.

It is an arithmetic number, because the mean of its divisors is an integer number (320116).

2640231 is an apocalyptic number.

640231 is a deficient number, since it is larger than the sum of its proper divisors (1).

640231 is an equidigital number, since it uses as much as digits as its factorization.

640231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 640231 is about 800.1443619748. The cubic root of 640231 is about 86.1877545710.

Adding to 640231 its reverse (132046), we get a palindrome (772277).

The spelling of 640231 in words is "six hundred forty thousand, two hundred thirty-one".