138491520 has 128 divisors (see below), whose sum is σ = 467519040. Its totient is φ = 34750464.

The previous prime is 138491489. The next prime is 138491531. The reversal of 138491520 is 25194831.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×138491520² = 38359802223820800, which contains 22 as substring.

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, 30519 + ... + 34761.

Almost surely, 2^138491520 is an apocalyptic number.

138491520 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 138491520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (233759520).

138491520 is an abundant number, since it is smaller than the sum of its proper divisors (329027520).

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

138491520 is a wasteful number, since it uses less digits than its factorization.

138491520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4282 (or 4270 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 138491520 is about 11768.2420097481. The cubic root of 138491520 is about 517.3777255514.

The spelling of 138491520 in words is "one hundred thirty-eight million, four hundred ninety-one thousand, five hundred twenty".