15997940 has 48 divisors (see below), whose sum is σ = 38640000. Its totient is φ = 5450112.

The previous prime is 15997889. The next prime is 15997957. The reversal of 15997940 is 4979951.

It is a junction number, because it is equal to n+sod(n) for n = 15997891 and 15997900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31811 + ... + 32309.

It is an arithmetic number, because the mean of its divisors is an integer number (805000).

Almost surely, 2^15997940 is an apocalyptic number.

15997940 is a gapful number since it is divisible by the number (10) 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 15997940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19320000).

15997940 is an abundant number, since it is smaller than the sum of its proper divisors (22642060).

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

15997940 is a wasteful number, since it uses less digits than its factorization.

15997940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744 (or 742 counting only the distinct ones).

The product of its (nonzero) digits is 102060, while the sum is 44.

The square root of 15997940 is about 3999.7424917112. The cubic root of 15997940 is about 251.9733951925.

The spelling of 15997940 in words is "fifteen million, nine hundred ninety-seven thousand, nine hundred forty".