1661319071 has 4 divisors (see below), whose sum is σ = 1661410032. Its totient is φ = 1661228112.

The previous prime is 1661319029. The next prime is 1661319113. The reversal of 1661319071 is 1709131661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1709131661 = 10193 ⋅167677.

It is an interprime number because it is at equal distance from previous prime (1661319029) and next prime (1661319113).

It is a cyclic number.

It is not a de Polignac number, because 1661319071 - 2³⁰ = 587577247 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 (1661319001) 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, 7526 + ... + 58131.

It is an arithmetic number, because the mean of its divisors is an integer number (415352508).

Almost surely, 2^1661319071 is an apocalyptic number.

1661319071 is a deficient number, since it is larger than the sum of its proper divisors (90961).

1661319071 is an equidigital number, since it uses as much as digits as its factorization.

1661319071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90960.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 1661319071 is about 40759.2820226265. The cubic root of 1661319071 is about 1184.3616877166.

The spelling of 1661319071 in words is "one billion, six hundred sixty-one million, three hundred nineteen thousand, seventy-one".