291521 has 2 divisors, whose sum is σ = 291522. Its totient is φ = 291520.

The previous prime is 291509. The next prime is 291539. The reversal of 291521 is 125192.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 287296 + 4225 = 536^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 291521 - 2⁶ = 291457 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 291493 and 291502.

It is not a weakly prime, because it can be changed into another prime (291721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145760 + 145761.

It is an arithmetic number, because the mean of its divisors is an integer number (145761).

2²⁹¹⁵²¹ is an apocalyptic number.

It is an amenable number.

291521 is a deficient number, since it is larger than the sum of its proper divisors (1).

291521 is an equidigital number, since it uses as much as digits as its factorization.

291521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 180, while the sum is 20.

The square root of 291521 is about 539.9268468969. The cubic root of 291521 is about 66.3065779884.

The spelling of 291521 in words is "two hundred ninety-one thousand, five hundred twenty-one".