1661199317 has 4 divisors (see below), whose sum is σ = 1748630880. Its totient is φ = 1573767756.

The previous prime is 1661199313. The next prime is 1661199343. The reversal of 1661199317 is 7139911661.

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.

It is a cyclic number.

It is not a de Polignac number, because 1661199317 - 2² = 1661199313 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 (1661199313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43715753 + ... + 43715790.

It is an arithmetic number, because the mean of its divisors is an integer number (437157720).

Almost surely, 2^1661199317 is an apocalyptic number.

It is an amenable number.

1661199317 is a deficient number, since it is larger than the sum of its proper divisors (87431563).

1661199317 is an equidigital number, since it uses as much as digits as its factorization.

1661199317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87431562.

The product of its digits is 61236, while the sum is 44.

The square root of 1661199317 is about 40757.8129565363. The cubic root of 1661199317 is about 1184.3332293147. Note that the first 3 decimals are identical.

The spelling of 1661199317 in words is "one billion, six hundred sixty-one million, one hundred ninety-nine thousand, three hundred seventeen".