661511116011 has 4 divisors (see below), whose sum is σ = 882014821352. Its totient is φ = 441007410672.

The previous prime is 661511116009. The next prime is 661511116027. The reversal of 661511116011 is 110611115166.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 661511116011 - 2¹ = 661511116009 is a prime.

It is a super-2 number, since 2×661511116011² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661511116011.

It is not an unprimeable number, because it can be changed into a prime (661511116001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110251852666 + ... + 110251852671.

It is an arithmetic number, because the mean of its divisors is an integer number (220503705338).

Almost surely, 2^661511116011 is an apocalyptic number.

661511116011 is a deficient number, since it is larger than the sum of its proper divisors (220503705341).

661511116011 is a wasteful number, since it uses less digits than its factorization.

661511116011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220503705340.

The product of its (nonzero) digits is 1080, while the sum is 30.

The spelling of 661511116011 in words is "six hundred sixty-one billion, five hundred eleven million, one hundred sixteen thousand, eleven".