38720640 has 256 divisors, whose sum is σ = 146488320. Its totient is φ = 8515584.

The previous prime is 38720623. The next prime is 38720641. The reversal of 38720640 is 4602783.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 38720598 and 38720607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (38720641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 577887 + ... + 577953.

It is an arithmetic number, because the mean of its divisors is an integer number (572220).

Almost surely, 2^38720640 is an apocalyptic number.

38720640 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 38720640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73244160).

38720640 is an abundant number, since it is smaller than the sum of its proper divisors (107767680).

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

38720640 is a wasteful number, since it uses less digits than its factorization.

38720640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 38720640 is about 6222.5911001768. The cubic root of 38720640 is about 338.3094862682.

The spelling of 38720640 in words is "thirty-eight million, seven hundred twenty thousand, six hundred forty".