15949921 has 8 divisors (see below), whose sum is σ = 17214120. Its totient is φ = 14691072.

The previous prime is 15949919. The next prime is 15949933. The reversal of 15949921 is 12994951.

It can be written as a sum of positive squares in 4 ways, for example, as 69696 + 15880225 = 264^2 + 3985^2 .

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 15949921 - 2¹ = 15949919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15949421) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 6675 + ... + 8743.

It is an arithmetic number, because the mean of its divisors is an integer number (2151765).

Almost surely, 2^15949921 is an apocalyptic number.

It is an amenable number.

15949921 is a deficient number, since it is larger than the sum of its proper divisors (1264199).

15949921 is a wasteful number, since it uses less digits than its factorization.

15949921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2675.

The product of its digits is 29160, while the sum is 40.

The square root of 15949921 is about 3993.7352190650. The cubic root of 15949921 is about 251.7210369399.

The spelling of 15949921 in words is "fifteen million, nine hundred forty-nine thousand, nine hundred twenty-one".