16410721 has 4 divisors (see below), whose sum is σ = 16854292. Its totient is φ = 15967152.

The previous prime is 16410703. The next prime is 16410731. The reversal of 16410721 is 12701461.

16410721 = 2864² + 2865².

16410721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12701461 = 59 ⋅215279.

It can be written as a sum of positive squares in 2 ways, for example, as 8208225 + 8202496 = 2865^2 + 2864^2 .

It is a cyclic number.

It is not a de Polignac number, because 16410721 - 2⁵ = 16410689 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16410692 and 16410701.

It is not an unprimeable number, because it can be changed into a prime (16410731) 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, 221730 + ... + 221803.

It is an arithmetic number, because the mean of its divisors is an integer number (4213573).

Almost surely, 2^16410721 is an apocalyptic number.

16410721 is the 2865-th centered square number.

It is an amenable number.

16410721 is a deficient number, since it is larger than the sum of its proper divisors (443571).

16410721 is an equidigital number, since it uses as much as digits as its factorization.

16410721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 443570.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 16410721 is about 4051.0148111307. The cubic root of 16410721 is about 254.1221693072.

The spelling of 16410721 in words is "sixteen million, four hundred ten thousand, seven hundred twenty-one".