16423921 has 4 divisors (see below), whose sum is σ = 17390052. Its totient is φ = 15457792.

The previous prime is 16423919. The next prime is 16423951. The reversal of 16423921 is 12932461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8381025 + 8042896 = 2895^2 + 2836^2 .

It is a cyclic number.

It is not a de Polignac number, because 16423921 - 2¹ = 16423919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16423921.

It is not an unprimeable number, because it can be changed into a prime (16423951) 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, 483040 + ... + 483073.

It is an arithmetic number, because the mean of its divisors is an integer number (4347513).

Almost surely, 2^16423921 is an apocalyptic number.

It is an amenable number.

16423921 is a deficient number, since it is larger than the sum of its proper divisors (966131).

16423921 is an equidigital number, since it uses as much as digits as its factorization.

16423921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 966130.

The product of its digits is 2592, while the sum is 28.

The square root of 16423921 is about 4052.6437050400. The cubic root of 16423921 is about 254.1902856250.

The spelling of 16423921 in words is "sixteen million, four hundred twenty-three thousand, nine hundred twenty-one".