145242733721 has 2 divisors, whose sum is σ = 145242733722. Its totient is φ = 145242733720.

The previous prime is 145242733703. The next prime is 145242733729. The reversal of 145242733721 is 127337242541.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105617850121 + 39624883600 = 324989^2 + 199060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145242733721 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (145242733729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72621366860 + 72621366861.

It is an arithmetic number, because the mean of its divisors is an integer number (72621366861).

Almost surely, 2^145242733721 is an apocalyptic number.

It is an amenable number.

145242733721 is a deficient number, since it is larger than the sum of its proper divisors (1).

145242733721 is an equidigital number, since it uses as much as digits as its factorization.

145242733721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 41.

The spelling of 145242733721 in words is "one hundred forty-five billion, two hundred forty-two million, seven hundred thirty-three thousand, seven hundred twenty-one".