1661001001011 has 32 divisors (see below), whose sum is σ = 2685179082240. Its totient is φ = 1006392391200.

The previous prime is 1661001000983. The next prime is 1661001001103. The reversal of 1661001001011 is 1101001001661.

1661001001011 is a `hidden beast` number, since 1 + 661 + 0 + 0 + 1 + 0 + 0 + 1 + 0 + 1 + 1 = 666.

It is not a de Polignac number, because 1661001001011 - 2¹⁵ = 1661000968243 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661001001411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 328561 + ... + 1852013.

It is an arithmetic number, because the mean of its divisors is an integer number (83911846320).

Almost surely, 2^{1661001001011} is an apocalyptic number.

1661001001011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1661001001011 is a deficient number, since it is larger than the sum of its proper divisors (1024178081229).

1661001001011 is a wasteful number, since it uses less digits than its factorization.

1661001001011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1527144 (or 1527138 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 18.

Adding to 1661001001011 its reverse (1101001001661), we get a palindrome (2762002002672).

The spelling of 1661001001011 in words is "one trillion, six hundred sixty-one billion, one million, one thousand, eleven".