1611511681 has 8 divisors (see below), whose sum is σ = 1735809320. Its totient is φ = 1487261952.

The previous prime is 1611511679. The next prime is 1611511687. The reversal of 1611511681 is 1861151161.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 332734081 + 1278777600 = 18241^2 + 35760^2 .

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 1611511681 - 2¹ = 1611511679 is a prime.

It is a super-2 number, since 2×1611511681² = 5193939795998891522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1611511687) 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 7 ways as a sum of consecutive naturals, for example, 90265 + ... + 106633.

It is an arithmetic number, because the mean of its divisors is an integer number (216976165).

Almost surely, 2^1611511681 is an apocalyptic number.

It is an amenable number.

1611511681 is a deficient number, since it is larger than the sum of its proper divisors (124297639).

1611511681 is a wasteful number, since it uses less digits than its factorization.

1611511681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23955.

The product of its digits is 1440, while the sum is 31.

The square root of 1611511681 is about 40143.6381136538. The cubic root of 1611511681 is about 1172.4054247892.

The spelling of 1611511681 in words is "one billion, six hundred eleven million, five hundred eleven thousand, six hundred eighty-one".