38991540 has 192 divisors, whose sum is σ = 136249344. Its totient is φ = 8128512.

The previous prime is 38991527. The next prime is 38991551. The reversal of 38991540 is 4519983.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 306957 + ... + 307083.

It is an arithmetic number, because the mean of its divisors is an integer number (709632).

Almost surely, 2^38991540 is an apocalyptic number.

38991540 is a gapful number since it is divisible by the number (30) 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 38991540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68124672).

38991540 is an abundant number, since it is smaller than the sum of its proper divisors (97257804).

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

38991540 is a wasteful number, since it uses less digits than its factorization.

38991540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 38991540 is about 6244.3206195710. The cubic root of 38991540 is about 339.0966214608.

The spelling of 38991540 in words is "thirty-eight million, nine hundred ninety-one thousand, five hundred forty".