15978740 has 12 divisors (see below), whose sum is σ = 33555396. Its totient is φ = 6391488.

The previous prime is 15978719. The next prime is 15978749. The reversal of 15978740 is 4787951.

It can be written as a sum of positive squares in 2 ways, for example, as 8988004 + 6990736 = 2998^2 + 2644^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15978749) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399449 + ... + 399488.

It is an arithmetic number, because the mean of its divisors is an integer number (2796283).

Almost surely, 2^15978740 is an apocalyptic number.

15978740 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15978740 is an abundant number, since it is smaller than the sum of its proper divisors (17576656).

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

15978740 is a wasteful number, since it uses less digits than its factorization.

15978740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798946 (or 798944 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 41.

The square root of 15978740 is about 3997.3416166247. The cubic root of 15978740 is about 251.8725525031.

The spelling of 15978740 in words is "fifteen million, nine hundred seventy-eight thousand, seven hundred forty".