138987900 has 90 divisors (see below), whose sum is σ = 450570120. Its totient is φ = 37061280.

The previous prime is 138987859. The next prime is 138987929. The reversal of 138987900 is 9789831.

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 480 + ... + 16679.

Almost surely, 2^138987900 is an apocalyptic number.

138987900 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 138987900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (225285060).

138987900 is an abundant number, since it is smaller than the sum of its proper divisors (311582220).

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

138987900 is a wasteful number, since it uses less digits than its factorization.

138987900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17185 (or 17169 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 138987900 is about 11789.3129570811. The cubic root of 138987900 is about 517.9951153120.

The spelling of 138987900 in words is "one hundred thirty-eight million, nine hundred eighty-seven thousand, nine hundred".