1661616611 has 4 divisors (see below), whose sum is σ = 1662502800. Its totient is φ = 1660730424.

The previous prime is 1661616599. The next prime is 1661616613. The reversal of 1661616611 is 1166161661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1661616611 - 2¹⁰ = 1661615587 is a prime.

It is a super-2 number, since 2×1661616611² = 5521939523902250642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661616613) 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, 440276 + ... + 444033.

It is an arithmetic number, because the mean of its divisors is an integer number (415625700).

Almost surely, 2^1661616611 is an apocalyptic number.

1661616611 is a deficient number, since it is larger than the sum of its proper divisors (886189).

1661616611 is an equidigital number, since it uses as much as digits as its factorization.

1661616611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886188.

The product of its digits is 7776, while the sum is 35.

The square root of 1661616611 is about 40762.9318253729. The cubic root of 1661616611 is about 1184.4323893551.

The spelling of 1661616611 in words is "one billion, six hundred sixty-one million, six hundred sixteen thousand, six hundred eleven".