21434845 has 4 divisors (see below), whose sum is σ = 25721820. Its totient is φ = 17147872.

The previous prime is 21434839. The next prime is 21434879. The reversal of 21434845 is 54843412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6895876 + 14538969 = 2626^2 + 3813^2 .

It is a cyclic number.

It is not a de Polignac number, because 21434845 - 2³ = 21434837 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 2143480 + ... + 2143489.

It is an arithmetic number, because the mean of its divisors is an integer number (6430455).

Almost surely, 2^21434845 is an apocalyptic number.

It is an amenable number.

21434845 is a deficient number, since it is larger than the sum of its proper divisors (4286975).

21434845 is an equidigital number, since it uses as much as digits as its factorization.

21434845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4286974.

The product of its digits is 15360, while the sum is 31.

The square root of 21434845 is about 4629.7780724350. The cubic root of 21434845 is about 277.7837154583.

The spelling of 21434845 in words is "twenty-one million, four hundred thirty-four thousand, eight hundred forty-five".