11781997 has 2 divisors, whose sum is σ = 11781998. Its totient is φ = 11781996.

The previous prime is 11781989. The next prime is 11782019. The reversal of 11781997 is 79918711.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11737476 + 44521 = 3426^2 + 211^2 .

It is a cyclic number.

It is not a de Polignac number, because 11781997 - 2³ = 11781989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11781907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5890998 + 5890999.

It is an arithmetic number, because the mean of its divisors is an integer number (5890999).

Almost surely, 2^11781997 is an apocalyptic number.

It is an amenable number.

11781997 is a deficient number, since it is larger than the sum of its proper divisors (1).

11781997 is an equidigital number, since it uses as much as digits as its factorization.

11781997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31752, while the sum is 43.

The square root of 11781997 is about 3432.4913692535. The cubic root of 11781997 is about 227.5479720114.

The spelling of 11781997 in words is "eleven million, seven hundred eighty-one thousand, nine hundred ninety-seven".