155442221 has 8 divisors (see below), whose sum is σ = 169744800. Its totient is φ = 141168240.

The previous prime is 155442197. The next prime is 155442227. The reversal of 155442221 is 122244551.

155442221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155442221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155442227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5150 + ... + 18368.

It is an arithmetic number, because the mean of its divisors is an integer number (21218100).

Almost surely, 2^155442221 is an apocalyptic number.

155442221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

155442221 is a deficient number, since it is larger than the sum of its proper divisors (14302579).

155442221 is a wasteful number, since it uses less digits than its factorization.

155442221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14299.

The product of its digits is 3200, while the sum is 26.

The square root of 155442221 is about 12467.6469712613. The cubic root of 155442221 is about 537.6789046426.

Adding to 155442221 its reverse (122244551), we get a palindrome (277686772).

The spelling of 155442221 in words is "one hundred fifty-five million, four hundred forty-two thousand, two hundred twenty-one".