15978040 has 32 divisors (see below), whose sum is σ = 38717280. Its totient is φ = 5899392.

The previous prime is 15978037. The next prime is 15978041. The reversal of 15978040 is 4087951.

It is a happy number.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 15977987 and 15978005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15978041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14844 + ... + 15883.

It is an arithmetic number, because the mean of its divisors is an integer number (1209915).

Almost surely, 2^15978040 is an apocalyptic number.

15978040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15978040 is an abundant number, since it is smaller than the sum of its proper divisors (22739240).

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

15978040 is a wasteful number, since it uses less digits than its factorization.

15978040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30751 (or 30747 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 15978040 is about 3997.2540574750. The cubic root of 15978040 is about 251.8688744208.

The spelling of 15978040 in words is "fifteen million, nine hundred seventy-eight thousand, forty".