21471451 has 4 divisors (see below), whose sum is σ = 21823504. Its totient is φ = 21119400.

The previous prime is 21471449. The next prime is 21471467. The reversal of 21471451 is 15417412.

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

It is a cyclic number.

It is not a de Polignac number, because 21471451 - 2¹ = 21471449 is a prime.

It is a super-2 number, since 2×21471451² = 922046416090802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21471481) 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 3 ways as a sum of consecutive naturals, for example, 175935 + ... + 176056.

It is an arithmetic number, because the mean of its divisors is an integer number (5455876).

Almost surely, 2^21471451 is an apocalyptic number.

21471451 is a deficient number, since it is larger than the sum of its proper divisors (352053).

21471451 is an equidigital number, since it uses as much as digits as its factorization.

21471451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352052.

The product of its digits is 1120, while the sum is 25.

The square root of 21471451 is about 4633.7297072661. The cubic root of 21471451 is about 277.9417566854.

Adding to 21471451 its reverse (15417412), we get a palindrome (36888863).

The spelling of 21471451 in words is "twenty-one million, four hundred seventy-one thousand, four hundred fifty-one".