155533121 has 4 divisors (see below), whose sum is σ = 156082992. Its totient is φ = 154983252.

The previous prime is 155533109. The next prime is 155533123. The reversal of 155533121 is 121335551.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 155533121 - 2⁶ = 155533057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155533123) 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 3 ways as a sum of consecutive naturals, for example, 274511 + ... + 275076.

It is an arithmetic number, because the mean of its divisors is an integer number (39020748).

Almost surely, 2^155533121 is an apocalyptic number.

It is an amenable number.

155533121 is a deficient number, since it is larger than the sum of its proper divisors (549871).

155533121 is an equidigital number, since it uses as much as digits as its factorization.

155533121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549870.

The product of its digits is 2250, while the sum is 26.

The square root of 155533121 is about 12471.2918737395. The cubic root of 155533121 is about 537.7836927500.

Adding to 155533121 its reverse (121335551), we get a palindrome (276868672).

The spelling of 155533121 in words is "one hundred fifty-five million, five hundred thirty-three thousand, one hundred twenty-one".