155531661 has 8 divisors (see below), whose sum is σ = 208749504. Its totient is φ = 103000800.

The previous prime is 155531653. The next prime is 155531689. The reversal of 155531661 is 166135551.

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

It is not a de Polignac number, because 155531661 - 2³ = 155531653 is a prime.

It is a Smith number, since the sum of its digits (33) 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 (155531161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171216 + ... + 172121.

It is an arithmetic number, because the mean of its divisors is an integer number (26093688).

Almost surely, 2^155531661 is an apocalyptic number.

It is an amenable number.

155531661 is a deficient number, since it is larger than the sum of its proper divisors (53217843).

155531661 is a wasteful number, since it uses less digits than its factorization.

155531661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343491.

The product of its digits is 13500, while the sum is 33.

The square root of 155531661 is about 12471.2333391690. The cubic root of 155531661 is about 537.7820100073.

The spelling of 155531661 in words is "one hundred fifty-five million, five hundred thirty-one thousand, six hundred sixty-one".