140639561 has 2 divisors, whose sum is σ = 140639562. Its totient is φ = 140639560.

The previous prime is 140639533. The next prime is 140639563. The reversal of 140639561 is 165936041.

140639561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93799225 + 46840336 = 9685^2 + 6844^2 .

It is a cyclic number.

It is not a de Polignac number, because 140639561 - 2¹⁸ = 140377417 is a prime.

It is a super-2 number, since 2×140639561² = 39558972236545442, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 140639563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (140639563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 70319780 + 70319781.

It is an arithmetic number, because the mean of its divisors is an integer number (70319781).

Almost surely, 2^140639561 is an apocalyptic number.

It is an amenable number.

140639561 is a deficient number, since it is larger than the sum of its proper divisors (1).

140639561 is an equidigital number, since it uses as much as digits as its factorization.

140639561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 140639561 is about 11859.1551554063. The cubic root of 140639561 is about 520.0389036475.

The spelling of 140639561 in words is "one hundred forty million, six hundred thirty-nine thousand, five hundred sixty-one".