21036450 has 48 divisors (see below), whose sum is σ = 53076960. Its totient is φ = 5512320.

The previous prime is 21036443. The next prime is 21036451. The reversal of 21036450 is 5463012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21036451) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7662 + ... + 10038.

It is an arithmetic number, because the mean of its divisors is an integer number (1105770).

Almost surely, 2^21036450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21036450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26538480).

21036450 is an abundant number, since it is smaller than the sum of its proper divisors (32040510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21036450 is a wasteful number, since it uses less digits than its factorization.

21036450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2451 (or 2446 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21036450 is about 4586.5509917584. The cubic root of 21036450 is about 276.0519488437.

Adding to 21036450 its reverse (5463012), we get a palindrome (26499462).

The spelling of 21036450 in words is "twenty-one million, thirty-six thousand, four hundred fifty".