155242321 has 16 divisors (see below), whose sum is σ = 169827840. Its totient is φ = 141053760.

The previous prime is 155242313. The next prime is 155242333. The reversal of 155242321 is 123242551.

It is a cyclic number.

It is not a de Polignac number, because 155242321 - 2³ = 155242313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (155242301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 359976 + ... + 360406.

It is an arithmetic number, because the mean of its divisors is an integer number (10614240).

Almost surely, 2^155242321 is an apocalyptic number.

It is an amenable number.

155242321 is a deficient number, since it is larger than the sum of its proper divisors (14585519).

155242321 is a wasteful number, since it uses less digits than its factorization.

155242321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816.

The product of its digits is 2400, while the sum is 25.

The square root of 155242321 is about 12459.6276429113. The cubic root of 155242321 is about 537.4483192423.

Adding to 155242321 its reverse (123242551), we get a palindrome (278484872).

The spelling of 155242321 in words is "one hundred fifty-five million, two hundred forty-two thousand, three hundred twenty-one".