145017781 has 4 divisors (see below), whose sum is σ = 145057932. Its totient is φ = 144977632.

The previous prime is 145017751. The next prime is 145017787. The reversal of 145017781 is 187710541.

145017781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 105390756 + 39627025 = 10266^2 + 6295^2 .

It is a cyclic number.

It is not a de Polignac number, because 145017781 - 2⁵ = 145017749 is a prime.

It is a super-2 number, since 2×145017781² = 42060313612327922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145017787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14056 + ... + 22081.

It is an arithmetic number, because the mean of its divisors is an integer number (36264483).

Almost surely, 2^145017781 is an apocalyptic number.

It is an amenable number.

145017781 is a deficient number, since it is larger than the sum of its proper divisors (40151).

145017781 is an equidigital number, since it uses as much as digits as its factorization.

145017781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40150.

The product of its (nonzero) digits is 7840, while the sum is 34.

The square root of 145017781 is about 12042.3328719979. The cubic root of 145017781 is about 525.3802608649.

The spelling of 145017781 in words is "one hundred forty-five million, seventeen thousand, seven hundred eighty-one".