21016445 has 8 divisors (see below), whose sum is σ = 26089560. Its totient is φ = 16233280.

The previous prime is 21016441. The next prime is 21016459. The reversal of 21016445 is 54461012.

It can be written as a sum of positive squares in 4 ways, for example, as 241081 + 20775364 = 491^2 + 4558^2 .

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

It is not a de Polignac number, because 21016445 - 2² = 21016441 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21016445.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21016441) 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, 72326 + ... + 72615.

It is an arithmetic number, because the mean of its divisors is an integer number (3261195).

Almost surely, 2^21016445 is an apocalyptic number.

It is an amenable number.

21016445 is a deficient number, since it is larger than the sum of its proper divisors (5073115).

21016445 is a wasteful number, since it uses less digits than its factorization.

21016445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144975.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21016445 is about 4584.3696404195. The cubic root of 21016445 is about 275.9644155271.

Adding to 21016445 its reverse (54461012), we get a palindrome (75477457).

The spelling of 21016445 in words is "twenty-one million, sixteen thousand, four hundred forty-five".