155421698665 has 4 divisors (see below), whose sum is σ = 186506038404. Its totient is φ = 124337358928.

The previous prime is 155421698623. The next prime is 155421698737. The reversal of 155421698665 is 566896124551.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 71068628569 + 84353070096 = 266587^2 + 290436^2 .

It is a cyclic number.

It is not a de Polignac number, because 155421698665 - 2⁹ = 155421698153 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15542169862 + ... + 15542169871.

It is an arithmetic number, because the mean of its divisors is an integer number (46626509601).

Almost surely, 2^155421698665 is an apocalyptic number.

It is an amenable number.

155421698665 is a deficient number, since it is larger than the sum of its proper divisors (31084339739).

155421698665 is an equidigital number, since it uses as much as digits as its factorization.

155421698665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31084339738.

The product of its digits is 15552000, while the sum is 58.

The spelling of 155421698665 in words is "one hundred fifty-five billion, four hundred twenty-one million, six hundred ninety-eight thousand, six hundred sixty-five".