138020561 has 8 divisors (see below), whose sum is σ = 158152704. Its totient is φ = 117992160.

The previous prime is 138020557. The next prime is 138020563. The reversal of 138020561 is 165020831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 138020561 - 2² = 138020557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138020561.

It is not an unprimeable number, because it can be changed into a prime (138020563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23060 + ... + 28421.

It is an arithmetic number, because the mean of its divisors is an integer number (19769088).

Almost surely, 2^138020561 is an apocalyptic number.

It is an amenable number.

138020561 is a deficient number, since it is larger than the sum of its proper divisors (20132143).

138020561 is an equidigital number, since it uses as much as digits as its factorization.

138020561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51871.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 138020561 is about 11748.2152261524. The cubic root of 138020561 is about 516.7905887049.

The spelling of 138020561 in words is "one hundred thirty-eight million, twenty thousand, five hundred sixty-one".