1605054991 has 2 divisors, whose sum is σ = 1605054992. Its totient is φ = 1605054990.

The previous prime is 1605054961. The next prime is 1605055009. The reversal of 1605054991 is 1994505061.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1605054991 - 2⁷ = 1605054863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1605054901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802527495 + 802527496.

It is an arithmetic number, because the mean of its divisors is an integer number (802527496).

Almost surely, 2^1605054991 is an apocalyptic number.

1605054991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605054991 is an equidigital number, since it uses as much as digits as its factorization.

1605054991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48600, while the sum is 40.

The square root of 1605054991 is about 40063.1375581094. The cubic root of 1605054991 is about 1170.8375406622.

The spelling of 1605054991 in words is "one billion, six hundred five million, fifty-four thousand, nine hundred ninety-one".