145905421 has 2 divisors, whose sum is σ = 145905422. Its totient is φ = 145905420.

The previous prime is 145905401. The next prime is 145905469. The reversal of 145905421 is 124509541.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 86229796 + 59675625 = 9286^2 + 7725^2 .

It is a cyclic number.

It is not a de Polignac number, because 145905421 - 2¹⁵ = 145872653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145905401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72952710 + 72952711.

It is an arithmetic number, because the mean of its divisors is an integer number (72952711).

Almost surely, 2^145905421 is an apocalyptic number.

It is an amenable number.

145905421 is a deficient number, since it is larger than the sum of its proper divisors (1).

145905421 is an equidigital number, since it uses as much as digits as its factorization.

145905421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 145905421 is about 12079.1316326961. The cubic root of 145905421 is about 526.4500153514.

The spelling of 145905421 in words is "one hundred forty-five million, nine hundred five thousand, four hundred twenty-one".