1661199311 has 4 divisors (see below), whose sum is σ = 1733425392. Its totient is φ = 1588973232.

The previous prime is 1661199301. The next prime is 1661199313. The reversal of 1661199311 is 1139911661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1139911661 = 7 ⋅162844523.

It is a cyclic number.

It is not a de Polignac number, because 1661199311 - 2⁶ = 1661199247 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661199313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36113006 + ... + 36113051.

It is an arithmetic number, because the mean of its divisors is an integer number (433356348).

Almost surely, 2^1661199311 is an apocalyptic number.

1661199311 is a deficient number, since it is larger than the sum of its proper divisors (72226081).

1661199311 is an equidigital number, since it uses as much as digits as its factorization.

1661199311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72226080.

The product of its digits is 8748, while the sum is 38.

The square root of 1661199311 is about 40757.8128829308. The cubic root of 1661199311 is about 1184.3332278888. Note that the first 3 decimals are identical.

The spelling of 1661199311 in words is "one billion, six hundred sixty-one million, one hundred ninety-nine thousand, three hundred eleven".