21470121 has 12 divisors (see below), whose sum is σ = 32082180. Its totient is φ = 13819680.

The previous prime is 21470081. The next prime is 21470123. The reversal of 21470121 is 12107412.

It can be written as a sum of positive squares in 2 ways, for example, as 5978025 + 15492096 = 2445^2 + 3936^2 .

It is not a de Polignac number, because 21470121 - 2¹⁴ = 21453737 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21470094 and 21470103.

It is not an unprimeable number, because it can be changed into a prime (21470123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40870 + ... + 41391.

It is an arithmetic number, because the mean of its divisors is an integer number (2673515).

Almost surely, 2^21470121 is an apocalyptic number.

It is an amenable number.

21470121 is a deficient number, since it is larger than the sum of its proper divisors (10612059).

21470121 is a wasteful number, since it uses less digits than its factorization.

21470121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82296 (or 82293 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 21470121 is about 4633.5861921410. The cubic root of 21470121 is about 277.9360177445.

Adding to 21470121 its reverse (12107412), we get a palindrome (33577533).

The spelling of 21470121 in words is "twenty-one million, four hundred seventy thousand, one hundred twenty-one".