145393921 has 4 divisors (see below), whose sum is σ = 145599700. Its totient is φ = 145188144.

The previous prime is 145393883. The next prime is 145393931. The reversal of 145393921 is 129393541.

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 62583921 + 82810000 = 7911^2 + 9100^2 .

It is a cyclic number.

It is not a de Polignac number, because 145393921 - 2¹⁷ = 145262849 is a prime.

It is a super-2 number, since 2×145393921² = 42278784527508482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145393931) 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, 101826 + ... + 103243.

It is an arithmetic number, because the mean of its divisors is an integer number (36399925).

Almost surely, 2^145393921 is an apocalyptic number.

It is an amenable number.

145393921 is a deficient number, since it is larger than the sum of its proper divisors (205779).

145393921 is an equidigital number, since it uses as much as digits as its factorization.

145393921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205778.

The product of its digits is 29160, while the sum is 37.

The square root of 145393921 is about 12057.9401640579. The cubic root of 145393921 is about 525.8341038804.

It can be divided in two parts, 14 and 5393921, that added together give a palindrome (5393935).

The spelling of 145393921 in words is "one hundred forty-five million, three hundred ninety-three thousand, nine hundred twenty-one".