138555831 has 8 divisors (see below), whose sum is σ = 195608304. Its totient is φ = 86936960.

The previous prime is 138555829. The next prime is 138555871.

138555831 is nontrivially palindromic in base 10.

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 138555831 - 2¹ = 138555829 is a prime.

It is a super-2 number, since 2×138555831² = 38395436608201122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 138555831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138555811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1358340 + ... + 1358441.

It is an arithmetic number, because the mean of its divisors is an integer number (24451038).

Almost surely, 2^138555831 is an apocalyptic number.

138555831 is a deficient number, since it is larger than the sum of its proper divisors (57052473).

138555831 is a wasteful number, since it uses less digits than its factorization.

138555831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2716801.

The product of its digits is 72000, while the sum is 39.

The square root of 138555831 is about 11770.9740888339. The cubic root of 138555831 is about 517.4577976740.

The spelling of 138555831 in words is "one hundred thirty-eight million, five hundred fifty-five thousand, eight hundred thirty-one".