11891917 has 2 divisors, whose sum is σ = 11891918. Its totient is φ = 11891916.

The previous prime is 11891833. The next prime is 11891933. The reversal of 11891917 is 71919811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9523396 + 2368521 = 3086^2 + 1539^2 .

It is a cyclic number.

It is not a de Polignac number, because 11891917 - 2¹¹ = 11889869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11891617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5945958 + 5945959.

It is an arithmetic number, because the mean of its divisors is an integer number (5945959).

Almost surely, 2^11891917 is an apocalyptic number.

It is an amenable number.

11891917 is a deficient number, since it is larger than the sum of its proper divisors (1).

11891917 is an equidigital number, since it uses as much as digits as its factorization.

11891917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 37.

The square root of 11891917 is about 3448.4658907984. The cubic root of 11891917 is about 228.2534180822.

The spelling of 11891917 in words is "eleven million, eight hundred ninety-one thousand, nine hundred seventeen".