138780805 has 8 divisors (see below), whose sum is σ = 172279800. Its totient is φ = 107196096.

The previous prime is 138780799. The next prime is 138780869. The reversal of 138780805 is 508087831.

It can be written as a sum of positive squares in 4 ways, for example, as 57744801 + 81036004 = 7599^2 + 9002^2 .

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 138780805 - 2⁹ = 138780293 is a prime.

It is a super-2 number, since 2×138780805² = 38520223672896050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478410 + ... + 478699.

It is an arithmetic number, because the mean of its divisors is an integer number (21534975).

Almost surely, 2^138780805 is an apocalyptic number.

It is an amenable number.

138780805 is a deficient number, since it is larger than the sum of its proper divisors (33498995).

138780805 is an equidigital number, since it uses as much as digits as its factorization.

138780805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957143.

The product of its (nonzero) digits is 53760, while the sum is 40.

The square root of 138780805 is about 11780.5265162471. The cubic root of 138780805 is about 517.7377127543.

The spelling of 138780805 in words is "one hundred thirty-eight million, seven hundred eighty thousand, eight hundred five".