291649 has 2 divisors, whose sum is σ = 291650. Its totient is φ = 291648.

The previous prime is 291647. The next prime is 291661. The reversal of 291649 is 946192.

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., 291600 + 49 = 540^2 + 7^2 .

It is a cyclic number.

It is not a de Polignac number, because 291649 - 2¹ = 291647 is a prime.

Together with 291647, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 291649.

It is not a weakly prime, because it can be changed into another prime (291647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145824 + 145825.

It is an arithmetic number, because the mean of its divisors is an integer number (145825).

2²⁹¹⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

291649 is a deficient number, since it is larger than the sum of its proper divisors (1).

291649 is an equidigital number, since it uses as much as digits as its factorization.

291649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 31.

The square root of 291649 is about 540.0453684645. The cubic root of 291649 is about 66.3162811202.

It can be divided in two parts, 2916 and 49, that multiplied together give a square (142884 = 378²).

The spelling of 291649 in words is "two hundred ninety-one thousand, six hundred forty-nine".