15665600655661 has 16 divisors (see below), whose sum is σ = 17120879221248. Its totient is φ = 14215526362800.

The previous prime is 15665600655619. The next prime is 15665600655689. The reversal of 15665600655661 is 16655600656651.

It is a cyclic number.

It is not a de Polignac number, because 15665600655661 - 2¹⁹ = 15665600131373 is a prime.

It is a super-2 number, since 2×15665600655661² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 15665600655596 and 15665600655605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15665600655611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20009400 + ... + 20777566.

It is an arithmetic number, because the mean of its divisors is an integer number (1070054951328).

Almost surely, 2^{15665600655661} is an apocalyptic number.

15665600655661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15665600655661 is a deficient number, since it is larger than the sum of its proper divisors (1455278565587).

15665600655661 is a wasteful number, since it uses less digits than its factorization.

15665600655661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771552.

The product of its (nonzero) digits is 29160000, while the sum is 58.

The spelling of 15665600655661 in words is "fifteen trillion, six hundred sixty-five billion, six hundred million, six hundred fifty-five thousand, six hundred sixty-one".