145212121 has 4 divisors (see below), whose sum is σ = 145272244. Its totient is φ = 145152000.

The previous prime is 145212097. The next prime is 145212131. The reversal of 145212121 is 121212541.

145212121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121212541 = 1013 ⋅119657.

It can be written as a sum of positive squares in 2 ways, for example, as 74046025 + 71166096 = 8605^2 + 8436^2 .

It is a cyclic number.

It is not a de Polignac number, because 145212121 - 2⁷ = 145211993 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145212131) 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, 26280 + ... + 31321.

It is an arithmetic number, because the mean of its divisors is an integer number (36318061).

Almost surely, 2^145212121 is an apocalyptic number.

It is an amenable number.

145212121 is a deficient number, since it is larger than the sum of its proper divisors (60123).

145212121 is an equidigital number, since it uses as much as digits as its factorization.

145212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60122.

The product of its digits is 160, while the sum is 19.

The square root of 145212121 is about 12050.3992050056. The cubic root of 145212121 is about 525.6148454875.

Adding to 145212121 its reverse (121212541), we get a palindrome (266424662).

The spelling of 145212121 in words is "one hundred forty-five million, two hundred twelve thousand, one hundred twenty-one".