145720321 has 2 divisors, whose sum is σ = 145720322. Its totient is φ = 145720320.

The previous prime is 145720301. The next prime is 145720349. The reversal of 145720321 is 123027541.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130782096 + 14938225 = 11436^2 + 3865^2 .

It is a cyclic number.

It is not a de Polignac number, because 145720321 - 2⁷ = 145720193 is a prime.

It is not a weakly prime, because it can be changed into another prime (145720301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72860160 + 72860161.

It is an arithmetic number, because the mean of its divisors is an integer number (72860161).

Almost surely, 2^145720321 is an apocalyptic number.

It is an amenable number.

145720321 is a deficient number, since it is larger than the sum of its proper divisors (1).

145720321 is an equidigital number, since it uses as much as digits as its factorization.

145720321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 145720321 is about 12071.4672264808. The cubic root of 145720321 is about 526.2272977081.

Adding to 145720321 its reverse (123027541), we get a palindrome (268747862).

The spelling of 145720321 in words is "one hundred forty-five million, seven hundred twenty thousand, three hundred twenty-one".