155133421 has 4 divisors (see below), whose sum is σ = 156355072. Its totient is φ = 153911772.

The previous prime is 155133401. The next prime is 155133439. The reversal of 155133421 is 124331551.

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, and also an emirpimes, since its reverse is a distinct semiprime: 124331551 = 1879 ⋅66169.

It is a cyclic number.

It is not a de Polignac number, because 155133421 - 2¹¹ = 155131373 is a prime.

It is a super-2 number, since 2×155133421² = 48132756622326482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155133401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 610635 + ... + 610888.

It is an arithmetic number, because the mean of its divisors is an integer number (39088768).

Almost surely, 2^155133421 is an apocalyptic number.

It is an amenable number.

155133421 is a deficient number, since it is larger than the sum of its proper divisors (1221651).

155133421 is a wasteful number, since it uses less digits than its factorization.

155133421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1221650.

The product of its digits is 1800, while the sum is 25.

The square root of 155133421 is about 12455.2567617051. The cubic root of 155133421 is about 537.3226193850.

Adding to 155133421 its reverse (124331551), we get a palindrome (279464972).

The spelling of 155133421 in words is "one hundred fifty-five million, one hundred thirty-three thousand, four hundred twenty-one".