1661711811 has 8 divisors (see below), whose sum is σ = 2216807424. Its totient is φ = 1107212040.

The previous prime is 1661711789. The next prime is 1661711851. The reversal of 1661711811 is 1181171661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1661711811 - 2⁷ = 1661711683 is a prime.

It is a super-2 number, since 2×1661711811² = 5522572285633799442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661711851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142411 + ... + 153636.

It is an arithmetic number, because the mean of its divisors is an integer number (277100928).

Almost surely, 2^1661711811 is an apocalyptic number.

1661711811 is a deficient number, since it is larger than the sum of its proper divisors (555095613).

1661711811 is a wasteful number, since it uses less digits than its factorization.

1661711811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297921.

The product of its digits is 2016, while the sum is 33.

The square root of 1661711811 is about 40764.0995362341. The cubic root of 1661711811 is about 1184.4550090555.

The spelling of 1661711811 in words is "one billion, six hundred sixty-one million, seven hundred eleven thousand, eight hundred eleven".