16121421 has 6 divisors (see below), whose sum is σ = 23286510. Its totient is φ = 10747608.

The previous prime is 16121411. The next prime is 16121429. The reversal of 16121421 is 12412161.

It can be written as a sum of positive squares in only one way, i.e., 15093225 + 1028196 = 3885^2 + 1014^2 .

It is not a de Polignac number, because 16121421 - 2¹⁰ = 16120397 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16121394 and 16121403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16121429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 895626 + ... + 895643.

It is an arithmetic number, because the mean of its divisors is an integer number (3881085).

Almost surely, 2^16121421 is an apocalyptic number.

It is an amenable number.

16121421 is a deficient number, since it is larger than the sum of its proper divisors (7165089).

16121421 is a wasteful number, since it uses less digits than its factorization.

16121421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1791275 (or 1791272 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 16121421 is about 4015.1489387070. The cubic root of 16121421 is about 252.6200246292.

Adding to 16121421 its reverse (12412161), we get a palindrome (28533582).

The spelling of 16121421 in words is "sixteen million, one hundred twenty-one thousand, four hundred twenty-one".