21046451 has 4 divisors (see below), whose sum is σ = 21615312. Its totient is φ = 20477592.

The previous prime is 21046447. The next prime is 21046463. The reversal of 21046451 is 15464012.

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 21046451 - 2² = 21046447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21046951) 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, 284375 + ... + 284448.

It is an arithmetic number, because the mean of its divisors is an integer number (5403828).

Almost surely, 2^21046451 is an apocalyptic number.

21046451 is a deficient number, since it is larger than the sum of its proper divisors (568861).

21046451 is an equidigital number, since it uses as much as digits as its factorization.

21046451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568860.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21046451 is about 4587.6411149958. The cubic root of 21046451 is about 276.0956881335.

It can be divided in two parts, 2 and 1046451, that multiplied together give a palindrome (2092902).

The spelling of 21046451 in words is "twenty-one million, forty-six thousand, four hundred fifty-one".