1515111611661 has 48 divisors (see below), whose sum is σ = 2240213976000. Its totient is φ = 986523826176.

The previous prime is 1515111611647. The next prime is 1515111611669. The reversal of 1515111611661 is 1661161115151.

1515111611661 is a `hidden beast` number, since 1 + 515 + 1 + 11 + 61 + 16 + 61 = 666.

It is not a de Polignac number, because 1515111611661 - 2³³ = 1506521677069 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 (1515111611669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36538206 + ... + 36579648.

It is an arithmetic number, because the mean of its divisors is an integer number (46671124500).

Almost surely, 2^{1515111611661} is an apocalyptic number.

It is an amenable number.

1515111611661 is a deficient number, since it is larger than the sum of its proper divisors (725102364339).

1515111611661 is a wasteful number, since it uses less digits than its factorization.

1515111611661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42090 (or 42087 counting only the distinct ones).

The product of its digits is 5400, while the sum is 36.

The spelling of 1515111611661 in words is "one trillion, five hundred fifteen billion, one hundred eleven million, six hundred eleven thousand, six hundred sixty-one".