21440545 has 16 divisors (see below), whose sum is σ = 29738880. Its totient is φ = 14534784.

The previous prime is 21440539. The next prime is 21440579. The reversal of 21440545 is 54504412.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21440545 - 2³ = 21440537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 327 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (1858680).

Almost surely, 2^21440545 is an apocalyptic number.

It is an amenable number.

21440545 is a deficient number, since it is larger than the sum of its proper divisors (8298335).

21440545 is an equidigital number, since it uses as much as digits as its factorization.

21440545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6984.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 21440545 is about 4630.3936117786. The cubic root of 21440545 is about 277.8083362233.

Adding to 21440545 its reverse (54504412), we get a palindrome (75944957).

The spelling of 21440545 in words is "twenty-one million, four hundred forty thousand, five hundred forty-five".