138305690 has 16 divisors (see below), whose sum is σ = 249109992. Its totient is φ = 55286784.

The previous prime is 138305641. The next prime is 138305701. The reversal of 138305690 is 96503831.

It can be written as a sum of positive squares in 4 ways, for example, as 91259809 + 47045881 = 9553^2 + 6859^2 .

It is a super-2 number, since 2×138305690² = 38256927772752200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 138305690.

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, 16742 + ... + 23598.

Almost surely, 2^138305690 is an apocalyptic number.

138305690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138305690 is a deficient number, since it is larger than the sum of its proper divisors (110804302).

138305690 is a wasteful number, since it uses less digits than its factorization.

138305690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8881.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 138305690 is about 11760.3439575550. The cubic root of 138305690 is about 517.1462135728.

The spelling of 138305690 in words is "one hundred thirty-eight million, three hundred five thousand, six hundred ninety".