15972821 has 8 divisors (see below), whose sum is σ = 16445184. Its totient is φ = 15504480.

The previous prime is 15972811. The next prime is 15972839. The reversal of 15972821 is 12827951.

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 15972821 - 2¹⁸ = 15710677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15972811) 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, 8270 + ... + 10016.

It is an arithmetic number, because the mean of its divisors is an integer number (2055648).

Almost surely, 2^15972821 is an apocalyptic number.

It is an amenable number.

15972821 is a deficient number, since it is larger than the sum of its proper divisors (472363).

15972821 is a wasteful number, since it uses less digits than its factorization.

15972821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2011.

The product of its digits is 10080, while the sum is 35.

The square root of 15972821 is about 3996.6011810037. The cubic root of 15972821 is about 251.8414483034.

The spelling of 15972821 in words is "fifteen million, nine hundred seventy-two thousand, eight hundred twenty-one".