21465451 has 4 divisors (see below), whose sum is σ = 24531952. Its totient is φ = 18398952.

The previous prime is 21465449. The next prime is 21465467. The reversal of 21465451 is 15456412.

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 21465451 - 2¹ = 21465449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21465251) 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, 1533240 + ... + 1533253.

It is an arithmetic number, because the mean of its divisors is an integer number (6132988).

Almost surely, 2^21465451 is an apocalyptic number.

21465451 is a deficient number, since it is larger than the sum of its proper divisors (3066501).

21465451 is an equidigital number, since it uses as much as digits as its factorization.

21465451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3066500.

The product of its digits is 4800, while the sum is 28.

The square root of 21465451 is about 4633.0822354023. The cubic root of 21465451 is about 277.9158648489.

The spelling of 21465451 in words is "twenty-one million, four hundred sixty-five thousand, four hundred fifty-one".