155540321 has 8 divisors (see below), whose sum is σ = 156950784. Its totient is φ = 154136080.

The previous prime is 155540317. The next prime is 155540323. The reversal of 155540321 is 123045551.

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

It is not a de Polignac number, because 155540321 - 2² = 155540317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155540323) 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, 58736 + ... + 61326.

It is an arithmetic number, because the mean of its divisors is an integer number (19618848).

Almost surely, 2^155540321 is an apocalyptic number.

It is an amenable number.

155540321 is a deficient number, since it is larger than the sum of its proper divisors (1410463).

155540321 is a wasteful number, since it uses less digits than its factorization.

155540321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3111.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 155540321 is about 12471.5805333566. The cubic root of 155540321 is about 537.7919910528.

Adding to 155540321 its reverse (123045551), we get a palindrome (278585872).

The spelling of 155540321 in words is "one hundred fifty-five million, five hundred forty thousand, three hundred twenty-one".