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291661 is a prime number
BaseRepresentation
bin1000111001101001101
3112211002021
41013031031
533313121
610130141
72323216
oct1071515
9484067
10291661
1118a147
12120951
13a29a6
147840d
155b641
hex4734d

291661 has 2 divisors, whose sum is σ = 291662. Its totient is φ = 291660.

The previous prime is 291649. The next prime is 291677. The reversal of 291661 is 166192.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198025 + 93636 = 445^2 + 306^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-291661 is a prime.

It is a super-2 number, since 2×2916612 = 170132277842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (291691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145830 + 145831.

It is an arithmetic number, because the mean of its divisors is an integer number (145831).

2291661 is an apocalyptic number.

It is an amenable number.

291661 is a deficient number, since it is larger than the sum of its proper divisors (1).

291661 is an equidigital number, since it uses as much as digits as its factorization.

291661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

The square root of 291661 is about 540.0564785279. The cubic root of 291661 is about 66.3171906433.

The spelling of 291661 in words is "two hundred ninety-one thousand, six hundred sixty-one".