39978720 has 72 divisors (see below), whose sum is σ = 136432296. Its totient is φ = 10660608.

The previous prime is 39978709. The next prime is 39978721. The reversal of 39978720 is 2787993.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39978721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12442 + ... + 15321.

It is an arithmetic number, because the mean of its divisors is an integer number (1894893).

Almost surely, 2^39978720 is an apocalyptic number.

39978720 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

39978720 is an abundant number, since it is smaller than the sum of its proper divisors (96453576).

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

39978720 is a wasteful number, since it uses less digits than its factorization.

39978720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27784 (or 27773 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 39978720 is about 6322.8727648119. The cubic root of 39978720 is about 341.9345314305.

The spelling of 39978720 in words is "thirty-nine million, nine hundred seventy-eight thousand, seven hundred twenty".