138236690 has 16 divisors (see below), whose sum is σ = 263463192. Its totient is φ = 52041984.

The previous prime is 138236689. The next prime is 138236711. The reversal of 138236690 is 96632831.

It can be written as a sum of positive squares in 4 ways, for example, as 94848121 + 43388569 = 9739^2 + 6587^2 .

It is a super-3 number, since 3×138236690³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406409 + ... + 406748.

Almost surely, 2^138236690 is an apocalyptic number.

138236690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138236690 is a deficient number, since it is larger than the sum of its proper divisors (125226502).

138236690 is a wasteful number, since it uses less digits than its factorization.

138236690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 813181.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 138236690 is about 11757.4100039082. The cubic root of 138236690 is about 517.0601987351.

The spelling of 138236690 in words is "one hundred thirty-eight million, two hundred thirty-six thousand, six hundred ninety".