15978397 has 8 divisors (see below), whose sum is σ = 16454592. Its totient is φ = 15506400.

The previous prime is 15978383. The next prime is 15978421. The reversal of 15978397 is 79387951.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15978397 - 2⁷ = 15978269 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 15978397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15978097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7728 + ... + 9574.

It is an arithmetic number, because the mean of its divisors is an integer number (2056824).

Almost surely, 2^15978397 is an apocalyptic number.

It is an amenable number.

15978397 is a deficient number, since it is larger than the sum of its proper divisors (476195).

15978397 is a wasteful number, since it uses less digits than its factorization.

15978397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2099.

The product of its digits is 476280, while the sum is 49.

The square root of 15978397 is about 3997.2987128810. The cubic root of 15978397 is about 251.8707502562.

The spelling of 15978397 in words is "fifteen million, nine hundred seventy-eight thousand, three hundred ninety-seven".