21144413 has 4 divisors (see below), whose sum is σ = 22388220. Its totient is φ = 19900608.

The previous prime is 21144373. The next prime is 21144419. The reversal of 21144413 is 31444112.

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 16662724 + 4481689 = 4082^2 + 2117^2 .

It is not a de Polignac number, because 21144413 - 2¹⁶ = 21078877 is a prime.

It is a super-2 number, since 2×21144413² = 894172402229138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144419) 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, 621878 + ... + 621911.

It is an arithmetic number, because the mean of its divisors is an integer number (5597055).

Almost surely, 2^21144413 is an apocalyptic number.

It is an amenable number.

21144413 is a deficient number, since it is larger than the sum of its proper divisors (1243807).

21144413 is a wasteful number, since it uses less digits than its factorization.

21144413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1243806.

The product of its digits is 384, while the sum is 20.

The square root of 21144413 is about 4598.3054487496. The cubic root of 21144413 is about 276.5233933427.

Adding to 21144413 its reverse (31444112), we get a palindrome (52588525).

The spelling of 21144413 in words is "twenty-one million, one hundred forty-four thousand, four hundred thirteen".