1661656161015 has 12 divisors (see below), whose sum is σ = 2880204012504. Its totient is φ = 886216619184.

The previous prime is 1661656160981. The next prime is 1661656161017. The reversal of 1661656161015 is 5101616561661.

1661656161015 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 6 + 5 + 616 + 10 + 15 = 666.

It is not a de Polignac number, because 1661656161015 - 2⁷ = 1661656160887 is a prime.

It is a super-2 number, since 2×1661656161015² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 36925692467 = 1661656161015 / (1 + 6 + 6 + 1 + 6 + 5 + 6 + 1 + 6 + 1 + 0 + 1 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661656161017) 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 11 ways as a sum of consecutive naturals, for example, 18462846189 + ... + 18462846278.

It is an arithmetic number, because the mean of its divisors is an integer number (240017001042).

Almost surely, 2^{1661656161015} is an apocalyptic number.

1661656161015 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661656161015 is a deficient number, since it is larger than the sum of its proper divisors (1218547851489).

1661656161015 is a wasteful number, since it uses less digits than its factorization.

1661656161015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36925692478 (or 36925692475 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The spelling of 1661656161015 in words is "one trillion, six hundred sixty-one billion, six hundred fifty-six million, one hundred sixty-one thousand, fifteen".