291148021 has 2 divisors, whose sum is σ = 291148022. Its totient is φ = 291148020.

The previous prime is 291148019. The next prime is 291148049. The reversal of 291148021 is 120841192.

It is an a-pointer prime, because the next prime (291148049) can be obtained adding 291148021 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 287302500 + 3845521 = 16950^2 + 1961^2 .

It is a cyclic number.

It is not a de Polignac number, because 291148021 - 2¹ = 291148019 is a prime.

Together with 291148019, 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 (291148061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145574010 + 145574011.

It is an arithmetic number, because the mean of its divisors is an integer number (145574011).

Almost surely, 2^291148021 is an apocalyptic number.

It is an amenable number.

291148021 is a deficient number, since it is larger than the sum of its proper divisors (1).

291148021 is an equidigital number, since it uses as much as digits as its factorization.

291148021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 291148021 is about 17063.0601300001. The cubic root of 291148021 is about 662.7828784144.

The spelling of 291148021 in words is "two hundred ninety-one million, one hundred forty-eight thousand, twenty-one".