138649920 has 56 divisors (see below), whose sum is σ = 440216544. Its totient is φ = 36973056.

The previous prime is 138649883. The next prime is 138649921. The reversal of 138649920 is 29946831.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138649921) 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, 71254 + ... + 73173.

Almost surely, 2^138649920 is an apocalyptic number.

138649920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138649920 is an abundant number, since it is smaller than the sum of its proper divisors (301566624).

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

138649920 is a wasteful number, since it uses less digits than its factorization.

138649920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144447 (or 144437 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 42.

The square root of 138649920 is about 11774.9700636562. The cubic root of 138649920 is about 517.5749010585.

The spelling of 138649920 in words is "one hundred thirty-eight million, six hundred forty-nine thousand, nine hundred twenty".