15840401 has 4 divisors (see below), whose sum is σ = 15864612. Its totient is φ = 15816192.

The previous prime is 15840397. The next prime is 15840449. The reversal of 15840401 is 10404851.

15840401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 3980²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10404851 = 1861 ⋅5591.

It can be written as a sum of positive squares in 2 ways, for example, as 5180176 + 10660225 = 2276^2 + 3265^2 .

It is a cyclic number.

It is not a de Polignac number, because 15840401 - 2² = 15840397 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (15840901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11096 + ... + 12441.

It is an arithmetic number, because the mean of its divisors is an integer number (3966153).

Almost surely, 2^15840401 is an apocalyptic number.

It is an amenable number.

15840401 is a deficient number, since it is larger than the sum of its proper divisors (24211).

15840401 is an equidigital number, since it uses as much as digits as its factorization.

15840401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24210.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 15840401 is about 3980.0001256281. Note that the first 3 decimals coincide. The cubic root of 15840401 is about 251.1435663811.

The spelling of 15840401 in words is "fifteen million, eight hundred forty thousand, four hundred one".