138649940 has 48 divisors (see below), whose sum is σ = 342074880. Its totient is φ = 46538880.

The previous prime is 138649939. The next prime is 138649963. The reversal of 138649940 is 49946831.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 138649891 and 138649900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21380 + ... + 27099.

It is an arithmetic number, because the mean of its divisors is an integer number (7126560).

Almost surely, 2^138649940 is an apocalyptic number.

138649940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138649940 is an abundant number, since it is smaller than the sum of its proper divisors (203424940).

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

138649940 is a wasteful number, since it uses less digits than its factorization.

138649940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48512 (or 48510 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 138649940 is about 11774.9709129152. The cubic root of 138649940 is about 517.5749259449.

The spelling of 138649940 in words is "one hundred thirty-eight million, six hundred forty-nine thousand, nine hundred forty".