15997538 has 4 divisors (see below), whose sum is σ = 23996310. Its totient is φ = 7998768.

The previous prime is 15997517. The next prime is 15997543. The reversal of 15997538 is 83579951.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13786369 + 2211169 = 3713^2 + 1487^2 .

It is a super-2 number, since 2×15997538² = 511842444122888, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 15997492 and 15997501.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3999383 + ... + 3999386.

Almost surely, 2^15997538 is an apocalyptic number.

15997538 is a deficient number, since it is larger than the sum of its proper divisors (7998772).

15997538 is an equidigital number, since it uses as much as digits as its factorization.

15997538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7998771.

The product of its digits is 340200, while the sum is 47.

The square root of 15997538 is about 3999.6922381603. The cubic root of 15997538 is about 251.9712846259.

The spelling of 15997538 in words is "fifteen million, nine hundred ninety-seven thousand, five hundred thirty-eight".