138121090 has 16 divisors (see below), whose sum is σ = 263242872. Its totient is φ = 51998464.

The previous prime is 138121069. The next prime is 138121091. The reversal of 138121090 is 90121831.

It can be written as a sum of positive squares in 4 ways, for example, as 137804121 + 316969 = 11739^2 + 563^2 .

It is not an unprimeable number, because it can be changed into a prime (138121091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406069 + ... + 406408.

Almost surely, 2^138121090 is an apocalyptic number.

138121090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138121090 is a deficient number, since it is larger than the sum of its proper divisors (125121782).

138121090 is a wasteful number, since it uses less digits than its factorization.

138121090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812501.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 138121090 is about 11752.4929270347. The cubic root of 138121090 is about 516.9160285486.

The spelling of 138121090 in words is "one hundred thirty-eight million, one hundred twenty-one thousand, ninety".