1661636011 has 6 divisors (see below), whose sum is σ = 1932923580. Its totient is φ = 1424259396.

The previous prime is 1661635973. The next prime is 1661636017. The reversal of 1661636011 is 1106361661.

It is not a de Polignac number, because 1661636011 - 2⁷ = 1661635883 is a prime.

It is a super-2 number, since 2×1661636011² = 5522068466103984242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661636017) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16955421 + ... + 16955518.

It is an arithmetic number, because the mean of its divisors is an integer number (322153930).

Almost surely, 2^1661636011 is an apocalyptic number.

1661636011 is a deficient number, since it is larger than the sum of its proper divisors (271287569).

1661636011 is an equidigital number, since it uses as much as digits as its factorization.

1661636011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33910953 (or 33910946 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 1661636011 is about 40763.1697859722. The cubic root of 1661636011 is about 1184.4369989019.

Adding to 1661636011 its reverse (1106361661), we get a palindrome (2767997672).

The spelling of 1661636011 in words is "one billion, six hundred sixty-one million, six hundred thirty-six thousand, eleven".