1691020811 has 2 divisors, whose sum is σ = 1691020812. Its totient is φ = 1691020810.

The previous prime is 1691020801. The next prime is 1691020841. The reversal of 1691020811 is 1180201961.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1691020811 is a prime.

It is not a weakly prime, because it can be changed into another prime (1691020801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845510405 + 845510406.

It is an arithmetic number, because the mean of its divisors is an integer number (845510406).

Almost surely, 2^1691020811 is an apocalyptic number.

1691020811 is a deficient number, since it is larger than the sum of its proper divisors (1).

1691020811 is an equidigital number, since it uses as much as digits as its factorization.

1691020811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 29.

The square root of 1691020811 is about 41122.0234302740. The cubic root of 1691020811 is about 1191.3782047763.

The spelling of 1691020811 in words is "one billion, six hundred ninety-one million, twenty thousand, eight hundred eleven".