1616611661 has 8 divisors (see below), whose sum is σ = 1848106560. Its totient is φ = 1385254368.

The previous prime is 1616611643. The next prime is 1616611679. The reversal of 1616611661 is 1661166161.

It is an interprime number because it is at equal distance from previous prime (1616611643) and next prime (1616611679).

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

It is a cyclic number.

It is not a de Polignac number, because 1616611661 - 2²⁶ = 1549502797 is a prime.

It is a super-2 number, since 2×1616611661² = 5226866524962357842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1616611621) 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, 7856 + ... + 57401.

It is an arithmetic number, because the mean of its divisors is an integer number (231013320).

Almost surely, 2^1616611661 is an apocalyptic number.

It is an amenable number.

1616611661 is a deficient number, since it is larger than the sum of its proper divisors (231494899).

1616611661 is an equidigital number, since it uses as much as digits as its factorization.

1616611661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68803.

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

The square root of 1616611661 is about 40207.1095827591. The cubic root of 1616611661 is about 1173.6408999055.

The spelling of 1616611661 in words is "one billion, six hundred sixteen million, six hundred eleven thousand, six hundred sixty-one".