291021803134661 has 2 divisors, whose sum is σ = 291021803134662. Its totient is φ = 291021803134660.

The previous prime is 291021803134607. The next prime is 291021803134721. The reversal of 291021803134661 is 166431308120192.

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., 194402536294561 + 96619266840100 = 13942831^2 + 9829510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-291021803134661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (291021803164661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145510901567330 + 145510901567331.

It is an arithmetic number, because the mean of its divisors is an integer number (145510901567331).

Almost surely, 2^{291021803134661} is an apocalyptic number.

It is an amenable number.

291021803134661 is a deficient number, since it is larger than the sum of its proper divisors (1).

291021803134661 is an equidigital number, since it uses as much as digits as its factorization.

291021803134661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 47.

The spelling of 291021803134661 in words is "two hundred ninety-one trillion, twenty-one billion, eight hundred three million, one hundred thirty-four thousand, six hundred sixty-one".