661560101055 has 80 divisors (see below), whose sum is σ = 1359164625984. Its totient is φ = 301570283520.

The previous prime is 661560100997. The next prime is 661560101089. The reversal of 661560101055 is 550101065166.

It is not a de Polignac number, because 661560101055 - 2¹⁰ = 661560100031 is a prime.

It is a super-2 number, since 2×661560101055² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 670225 + ... + 1331285.

Almost surely, 2^661560101055 is an apocalyptic number.

661560101055 is an abundant number, since it is smaller than the sum of its proper divisors (697604524929).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661560101055 is a wasteful number, since it uses less digits than its factorization.

661560101055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661438 (or 661429 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The spelling of 661560101055 in words is "six hundred sixty-one billion, five hundred sixty million, one hundred one thousand, fifty-five".