138721164 has 24 divisors (see below), whose sum is σ = 325140480. Its totient is φ = 46032144.

The previous prime is 138721159. The next prime is 138721169. The reversal of 138721164 is 461127831.

It is an interprime number because it is at equal distance from previous prime (138721159) and next prime (138721169).

It is a super-2 number, since 2×138721164² = 38487122683029792, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138721169) 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, 23244 + ... + 28595.

It is an arithmetic number, because the mean of its divisors is an integer number (13547520).

Almost surely, 2^138721164 is an apocalyptic number.

It is an amenable number.

138721164 is an abundant number, since it is smaller than the sum of its proper divisors (186419316).

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

138721164 is a wasteful number, since it uses less digits than its factorization.

138721164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52069 (or 52067 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 138721164 is about 11777.9949057554. The cubic root of 138721164 is about 517.6635362635.

Adding to 138721164 its reverse (461127831), we get a palindrome (599848995).

The spelling of 138721164 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, one hundred sixty-four".