145706221 has 2 divisors, whose sum is σ = 145706222. Its totient is φ = 145706220.

The previous prime is 145706207. The next prime is 145706273. The reversal of 145706221 is 122607541.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 98783721 + 46922500 = 9939^2 + 6850^2 .

It is a cyclic number.

It is not a de Polignac number, because 145706221 - 2¹³ = 145698029 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 145706221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145706621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72853110 + 72853111.

It is an arithmetic number, because the mean of its divisors is an integer number (72853111).

Almost surely, 2^145706221 is an apocalyptic number.

It is an amenable number.

145706221 is a deficient number, since it is larger than the sum of its proper divisors (1).

145706221 is an equidigital number, since it uses as much as digits as its factorization.

145706221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 145706221 is about 12070.8831905540. The cubic root of 145706221 is about 526.2103244537.

The spelling of 145706221 in words is "one hundred forty-five million, seven hundred six thousand, two hundred twenty-one".