16698421 has 4 divisors (see below), whose sum is σ = 16713612. Its totient is φ = 16683232.

The previous prime is 16698379. The next prime is 16698427. The reversal of 16698421 is 12489661.

16698421 = 2889² + 2890².

It is a happy number.

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 8352100 + 8346321 = 2890^2 + 2889^2 .

It is a cyclic number.

It is not a de Polignac number, because 16698421 - 2⁷ = 16698293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16698427) 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, 5806 + ... + 8191.

It is an arithmetic number, because the mean of its divisors is an integer number (4178403).

Almost surely, 2^16698421 is an apocalyptic number.

16698421 is the 2890-th centered square number.

It is an amenable number.

16698421 is a deficient number, since it is larger than the sum of its proper divisors (15191).

16698421 is a wasteful number, since it uses less digits than its factorization.

16698421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15190.

The product of its digits is 20736, while the sum is 37.

The square root of 16698421 is about 4086.3701496560. The cubic root of 16698421 is about 255.5985988480.

The spelling of 16698421 in words is "sixteen million, six hundred ninety-eight thousand, four hundred twenty-one".