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640949 is a prime number
BaseRepresentation
bin10011100011110110101
31012120012212
42130132311
5131002244
621423205
75306441
oct2343665
91176185
10640949
113a8611
1226ab05
1319597a
14129821
15c9d9e
hex9c7b5

640949 has 2 divisors, whose sum is σ = 640950. Its totient is φ = 640948.

The previous prime is 640943. The next prime is 640957. The reversal of 640949 is 949046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 628849 + 12100 = 793^2 + 110^2 .

It is a cyclic number.

It is not a de Polignac number, because 640949 - 24 = 640933 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320474 + 320475.

It is an arithmetic number, because the mean of its divisors is an integer number (320475).

2640949 is an apocalyptic number.

It is an amenable number.

640949 is a deficient number, since it is larger than the sum of its proper divisors (1).

640949 is an equidigital number, since it uses as much as digits as its factorization.

640949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 640949 is about 800.5929052896. The cubic root of 640949 is about 86.2199615343.

The spelling of 640949 in words is "six hundred forty thousand, nine hundred forty-nine".