15994993 has 16 divisors (see below), whose sum is σ = 18998784. Its totient is φ = 13181760.

The previous prime is 15994981. The next prime is 15994997. The reversal of 15994993 is 39949951.

It is a cyclic number.

It is not a de Polignac number, because 15994993 - 2¹⁷ = 15863921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15994997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19671 + ... + 20467.

It is an arithmetic number, because the mean of its divisors is an integer number (1187424).

Almost surely, 2^15994993 is an apocalyptic number.

It is an amenable number.

15994993 is a deficient number, since it is larger than the sum of its proper divisors (3003791).

15994993 is an equidigital number, since it uses as much as digits as its factorization.

15994993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912.

The product of its digits is 393660, while the sum is 49.

The square root of 15994993 is about 3999.3740760274. The cubic root of 15994993 is about 251.9579221337.

The spelling of 15994993 in words is "fifteen million, nine hundred ninety-four thousand, nine hundred ninety-three".