1111555511661 has 32 divisors (see below), whose sum is σ = 1871409512448. Its totient is φ = 571819564800.

The previous prime is 1111555511653. The next prime is 1111555511747. The reversal of 1111555511661 is 1661155551111.

It is not a de Polignac number, because 1111555511661 - 2³ = 1111555511653 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1111555511761) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67678765 + ... + 67695186.

It is an arithmetic number, because the mean of its divisors is an integer number (58481547264).

Almost surely, 2^{1111555511661} is an apocalyptic number.

It is an amenable number.

1111555511661 is a deficient number, since it is larger than the sum of its proper divisors (759854000787).

1111555511661 is a wasteful number, since it uses less digits than its factorization.

1111555511661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135374001.

The product of its digits is 22500, while the sum is 39.

The spelling of 1111555511661 in words is "one trillion, one hundred eleven billion, five hundred fifty-five million, five hundred eleven thousand, six hundred sixty-one".