145921 has 4 divisors (see below), whose sum is σ = 146692. Its totient is φ = 145152.

The previous prime is 145903. The next prime is 145931. The reversal of 145921 is 129541.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 129541 = 281 ⋅461.

It can be written as a sum of positive squares in 2 ways, for example, as 26896 + 119025 = 164^2 + 345^2 .

It is a cyclic number.

It is not a de Polignac number, because 145921 - 2¹¹ = 143873 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 145892 and 145901.

It is not an unprimeable number, because it can be changed into a prime (145931) 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, 121 + ... + 553.

It is an arithmetic number, because the mean of its divisors is an integer number (36673).

It is a Proth number, since it is equal to 285 ⋅ 2⁹ + 1 and 285 < 2⁹.

2¹⁴⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

145921 is a deficient number, since it is larger than the sum of its proper divisors (771).

145921 is an equidigital number, since it uses as much as digits as its factorization.

145921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 770.

The product of its digits is 360, while the sum is 22.

The square root of 145921 is about 381.9960732782. The cubic root of 145921 is about 52.6468751856.

The spelling of 145921 in words is "one hundred forty-five thousand, nine hundred twenty-one".