21144407 has 8 divisors (see below), whose sum is σ = 21684672. Its totient is φ = 20608000.

The previous prime is 21144373. The next prime is 21144419. The reversal of 21144407 is 70444112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21144407 - 2¹⁰ = 21143383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12407 + ... + 14007.

It is an arithmetic number, because the mean of its divisors is an integer number (2710584).

Almost surely, 2^21144407 is an apocalyptic number.

21144407 is a deficient number, since it is larger than the sum of its proper divisors (540265).

21144407 is a wasteful number, since it uses less digits than its factorization.

21144407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1929.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 21144407 is about 4598.3047963353. The cubic root of 21144407 is about 276.5233671870.

Adding to 21144407 its reverse (70444112), we get a palindrome (91588519).

The spelling of 21144407 in words is "twenty-one million, one hundred forty-four thousand, four hundred seven".