138591840 has 48 divisors (see below), whose sum is σ = 436565808. Its totient is φ = 36957696.

The previous prime is 138591829. The next prime is 138591847. The reversal of 138591840 is 48195831.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×138591840² = 38415396229171200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138591847) 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, 143887 + ... + 144846.

It is an arithmetic number, because the mean of its divisors is an integer number (9095121).

Almost surely, 2^138591840 is an apocalyptic number.

138591840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138591840 is an abundant number, since it is smaller than the sum of its proper divisors (297973968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138591840 is a wasteful number, since it uses less digits than its factorization.

138591840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288751 (or 288743 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 138591840 is about 11772.5035570179. The cubic root of 138591840 is about 517.5026208180.

The spelling of 138591840 in words is "one hundred thirty-eight million, five hundred ninety-one thousand, eight hundred forty".