145242221 has 4 divisors (see below), whose sum is σ = 145270944. Its totient is φ = 145213500.

The previous prime is 145242157. The next prime is 145242269. The reversal of 145242221 is 122242541.

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 a cyclic number.

It is not a de Polignac number, because 145242221 - 2⁶ = 145242157 is a prime.

It is a super-2 number, since 2×145242221² = 42190605522025682, 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 (145242421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4535 + ... + 17636.

It is an arithmetic number, because the mean of its divisors is an integer number (36317736).

Almost surely, 2^145242221 is an apocalyptic number.

It is an amenable number.

145242221 is a deficient number, since it is larger than the sum of its proper divisors (28723).

145242221 is an equidigital number, since it uses as much as digits as its factorization.

145242221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28722.

The product of its digits is 1280, while the sum is 23.

The square root of 145242221 is about 12051.6480615723. The cubic root of 145242221 is about 525.6511599809.

Adding to 145242221 its reverse (122242541), we get a palindrome (267484762).

The spelling of 145242221 in words is "one hundred forty-five million, two hundred forty-two thousand, two hundred twenty-one".