21473121 has 8 divisors (see below), whose sum is σ = 28743264. Its totient is φ = 14259200.

The previous prime is 21473107. The next prime is 21473147. The reversal of 21473121 is 12137412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21473121 - 2⁷ = 21472993 is a prime.

It is a super-2 number, since 2×21473121² = 922189850961282, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21473171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13155 + ... + 14696.

It is an arithmetic number, because the mean of its divisors is an integer number (3592908).

Almost surely, 2^21473121 is an apocalyptic number.

It is an amenable number.

21473121 is a deficient number, since it is larger than the sum of its proper divisors (7270143).

21473121 is a wasteful number, since it uses less digits than its factorization.

21473121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28111.

The product of its digits is 336, while the sum is 21.

The square root of 21473121 is about 4633.9099041738. The cubic root of 21473121 is about 277.9489623885.

The spelling of 21473121 in words is "twenty-one million, four hundred seventy-three thousand, one hundred twenty-one".