21067451 has 4 divisors (see below), whose sum is σ = 21135504. Its totient is φ = 20999400.

The previous prime is 21067441. The next prime is 21067477. The reversal of 21067451 is 15476012.

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 21067451 - 2¹⁸ = 20805307 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21067451.

It is not an unprimeable number, because it can be changed into a prime (21067441) 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, 33560 + ... + 34181.

It is an arithmetic number, because the mean of its divisors is an integer number (5283876).

Almost surely, 2^21067451 is an apocalyptic number.

21067451 is a deficient number, since it is larger than the sum of its proper divisors (68053).

21067451 is an equidigital number, since it uses as much as digits as its factorization.

21067451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68052.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21067451 is about 4589.9293022878. The cubic root of 21067451 is about 276.1874863836.

The spelling of 21067451 in words is "twenty-one million, sixty-seven thousand, four hundred fifty-one".