145340021 has 4 divisors (see below), whose sum is σ = 153889452. Its totient is φ = 136790592.

The previous prime is 145340017. The next prime is 145340023. The reversal of 145340021 is 120043541.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 56415121 + 88924900 = 7511^2 + 9430^2 .

It is a cyclic number.

It is not a de Polignac number, because 145340021 - 2² = 145340017 is a prime.

It is a super-2 number, since 2×145340021² = 42247443408560882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 145339975 and 145340002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145340023) 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, 4274690 + ... + 4274723.

It is an arithmetic number, because the mean of its divisors is an integer number (38472363).

Almost surely, 2^145340021 is an apocalyptic number.

It is an amenable number.

145340021 is a deficient number, since it is larger than the sum of its proper divisors (8549431).

145340021 is an equidigital number, since it uses as much as digits as its factorization.

145340021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8549430.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 145340021 is about 12055.7049151014. The cubic root of 145340021 is about 525.7691172998.

Adding to 145340021 its reverse (120043541), we get a palindrome (265383562).

The spelling of 145340021 in words is "one hundred forty-five million, three hundred forty thousand, twenty-one".