1661056011 has 8 divisors (see below), whose sum is σ = 2460823760. Its totient is φ = 1107370656.

The previous prime is 1661055989. The next prime is 1661056051. The reversal of 1661056011 is 1106501661.

It is not a de Polignac number, because 1661056011 - 2⁶ = 1661055947 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 61520593 = 1661056011 / (1 + 6 + 6 + 1 + 0 + 5 + 6 + 0 + 1 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661056051) 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, 30760270 + ... + 30760323.

It is an arithmetic number, because the mean of its divisors is an integer number (307602970).

Almost surely, 2^1661056011 is an apocalyptic number.

1661056011 is a deficient number, since it is larger than the sum of its proper divisors (799767749).

1661056011 is an equidigital number, since it uses as much as digits as its factorization.

1661056011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61520602 (or 61520596 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 1661056011 is about 40756.0548998551. The cubic root of 1661056011 is about 1184.2991722057.

Adding to 1661056011 its reverse (1106501661), we get a palindrome (2767557672).

The spelling of 1661056011 in words is "one billion, six hundred sixty-one million, fifty-six thousand, eleven".