1661736961 has 16 divisors (see below), whose sum is σ = 1782798336. Its totient is φ = 1543401216.

The previous prime is 1661736919. The next prime is 1661736971. The reversal of 1661736961 is 1696371661.

It is a cyclic number.

It is not a de Polignac number, because 1661736961 - 2¹¹ = 1661734913 is a prime.

It is a super-2 number, since 2×1661736961² = 5522739455107031042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661736911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 423370 + ... + 427276.

It is an arithmetic number, because the mean of its divisors is an integer number (111424896).

Almost surely, 2^1661736961 is an apocalyptic number.

It is an amenable number.

1661736961 is a deficient number, since it is larger than the sum of its proper divisors (121061375).

1661736961 is a wasteful number, since it uses less digits than its factorization.

1661736961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4248.

The product of its digits is 244944, while the sum is 46.

The square root of 1661736961 is about 40764.4080172888. The cubic root of 1661736961 is about 1184.4609845990.

The spelling of 1661736961 in words is "one billion, six hundred sixty-one million, seven hundred thirty-six thousand, nine hundred sixty-one".