1911906691 has 2 divisors, whose sum is σ = 1911906692. Its totient is φ = 1911906690.

The previous prime is 1911906613. The next prime is 1911906701. The reversal of 1911906691 is 1966091191.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1911906691 is a prime.

It is not a weakly prime, because it can be changed into another prime (1911906611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 955953345 + 955953346.

It is an arithmetic number, because the mean of its divisors is an integer number (955953346).

Almost surely, 2^1911906691 is an apocalyptic number.

1911906691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1911906691 is an equidigital number, since it uses as much as digits as its factorization.

1911906691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26244, while the sum is 43.

The square root of 1911906691 is about 43725.3552415529. The cubic root of 1911906691 is about 1241.1441683081.

The spelling of 1911906691 in words is "one billion, nine hundred eleven million, nine hundred six thousand, six hundred ninety-one".