1663791541665 has 32 divisors (see below), whose sum is σ = 2936702563200. Its totient is φ = 797622904320.

The previous prime is 1663791541661. The next prime is 1663791541669. The reversal of 1663791541665 is 5661451973661.

It is an interprime number because it is at equal distance from previous prime (1663791541661) and next prime (1663791541669).

It is not a de Polignac number, because 1663791541665 - 2² = 1663791541661 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1663791541599 and 1663791541608.

It is not an unprimeable number, because it can be changed into a prime (1663791541661) 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, 56634670 + ... + 56664039.

It is an arithmetic number, because the mean of its divisors is an integer number (91771955100).

Almost surely, 2^{1663791541665} is an apocalyptic number.

1663791541665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1663791541665 is a deficient number, since it is larger than the sum of its proper divisors (1272911021535).

1663791541665 is a wasteful number, since it uses less digits than its factorization.

1663791541665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113298817.

The product of its digits is 24494400, while the sum is 60.

The spelling of 1663791541665 in words is "one trillion, six hundred sixty-three billion, seven hundred ninety-one million, five hundred forty-one thousand, six hundred sixty-five".