138951540 has 288 divisors, whose sum is σ = 550368000. Its totient is φ = 27537408.

The previous prime is 138951521. The next prime is 138951563. The reversal of 138951540 is 45159831.

138951540 is a `hidden beast` number, since 138 + 9 + 515 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 138951495 and 138951504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 278211 + ... + 278709.

It is an arithmetic number, because the mean of its divisors is an integer number (1911000).

Almost surely, 2^138951540 is an apocalyptic number.

138951540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138951540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (275184000).

138951540 is an abundant number, since it is smaller than the sum of its proper divisors (411416460).

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

138951540 is a wasteful number, since it uses less digits than its factorization.

138951540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551 (or 546 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 138951540 is about 11787.7707816194. The cubic root of 138951540 is about 517.9499412476.

The spelling of 138951540 in words is "one hundred thirty-eight million, nine hundred fifty-one thousand, five hundred forty".