138787121 has 12 divisors (see below), whose sum is σ = 154492800. Its totient is φ = 124564440.

The previous prime is 138787097. The next prime is 138787123. The reversal of 138787121 is 121787831.

It is a de Polignac number, because none of the positive numbers 2^k-138787121 is a prime.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (138787123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2300 + ... + 16818.

It is an arithmetic number, because the mean of its divisors is an integer number (12874400).

Almost surely, 2^138787121 is an apocalyptic number.

138787121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138787121 is a deficient number, since it is larger than the sum of its proper divisors (15705679).

138787121 is a wasteful number, since it uses less digits than its factorization.

138787121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14620 (or 14609 counting only the distinct ones).

The product of its digits is 18816, while the sum is 38.

The square root of 138787121 is about 11780.7945827096. The cubic root of 138787121 is about 517.7455668226.

The spelling of 138787121 in words is "one hundred thirty-eight million, seven hundred eighty-seven thousand, one hundred twenty-one".