145723021 has 2 divisors, whose sum is σ = 145723022. Its totient is φ = 145723020.

The previous prime is 145722991. The next prime is 145723049. The reversal of 145723021 is 120327541.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 124434025 + 21288996 = 11155^2 + 4614^2 .

It is an emirp because it is prime and its reverse (120327541) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 145723021 - 2⁷ = 145722893 is a prime.

It is equal to p_8217043 and since 145723021 and 8217043 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145723051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72861510 + 72861511.

It is an arithmetic number, because the mean of its divisors is an integer number (72861511).

Almost surely, 2^145723021 is an apocalyptic number.

It is an amenable number.

145723021 is a deficient number, since it is larger than the sum of its proper divisors (1).

145723021 is an equidigital number, since it uses as much as digits as its factorization.

145723021 is an odious number, because the sum of its binary digits is odd.

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

The square root of 145723021 is about 12071.5790599242. The cubic root of 145723021 is about 526.2305477809.

The spelling of 145723021 in words is "one hundred forty-five million, seven hundred twenty-three thousand, twenty-one".