155561066565 has 8 divisors (see below), whose sum is σ = 248897706528. Its totient is φ = 82965902160.

The previous prime is 155561066543. The next prime is 155561066567. The reversal of 155561066565 is 565660165551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 155561066565 - 2⁵ = 155561066533 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155561066567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5185368871 + ... + 5185368900.

It is an arithmetic number, because the mean of its divisors is an integer number (31112213316).

Almost surely, 2^155561066565 is an apocalyptic number.

155561066565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

155561066565 is a deficient number, since it is larger than the sum of its proper divisors (93336639963).

155561066565 is a wasteful number, since it uses less digits than its factorization.

155561066565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10370737779.

The product of its (nonzero) digits is 4050000, while the sum is 51.

The spelling of 155561066565 in words is "one hundred fifty-five billion, five hundred sixty-one million, sixty-six thousand, five hundred sixty-five".