161511666615507 has 24 divisors (see below), whose sum is σ = 233199421081200. Its totient is φ = 99387115122048.

The previous prime is 161511666615491. The next prime is 161511666615569. The reversal of 161511666615507 is 705516666115161.

It is not a de Polignac number, because 161511666615507 - 2⁴ = 161511666615491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161511666615107) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3294469 + ... + 18272297.

It is an arithmetic number, because the mean of its divisors is an integer number (9716642545050).

Almost surely, 2^{161511666615507} is an apocalyptic number.

161511666615507 is a deficient number, since it is larger than the sum of its proper divisors (71687754465693).

161511666615507 is a wasteful number, since it uses less digits than its factorization.

161511666615507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14999127 (or 14999114 counting only the distinct ones).

The product of its (nonzero) digits is 6804000, while the sum is 57.

The spelling of 161511666615507 in words is "one hundred sixty-one trillion, five hundred eleven billion, six hundred sixty-six million, six hundred fifteen thousand, five hundred seven".