1211139997 has 4 divisors (see below), whose sum is σ = 1211214816. Its totient is φ = 1211065180.

The previous prime is 1211139967. The next prime is 1211140001. The reversal of 1211139997 is 7999311121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7999311121 = 17 ⋅470547713.

It is a cyclic number.

It is not a de Polignac number, because 1211139997 - 2¹⁵ = 1211107229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211139967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1879 + ... + 49252.

It is an arithmetic number, because the mean of its divisors is an integer number (302803704).

Almost surely, 2^1211139997 is an apocalyptic number.

It is an amenable number.

1211139997 is a deficient number, since it is larger than the sum of its proper divisors (74819).

1211139997 is an equidigital number, since it uses as much as digits as its factorization.

1211139997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74818.

The product of its digits is 30618, while the sum is 43.

The square root of 1211139997 is about 34801.4367088487. The cubic root of 1211139997 is about 1065.9367827863.

The spelling of 1211139997 in words is "one billion, two hundred eleven million, one hundred thirty-nine thousand, nine hundred ninety-seven".