21044554 has 4 divisors (see below), whose sum is σ = 31566834. Its totient is φ = 10522276.

The previous prime is 21044531. The next prime is 21044557. The reversal of 21044554 is 45544012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18688329 + 2356225 = 4323^2 + 1535^2 .

It is not an unprimeable number, because it can be changed into a prime (21044557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5261137 + ... + 5261140.

Almost surely, 2^21044554 is an apocalyptic number.

21044554 is a deficient number, since it is larger than the sum of its proper divisors (10522280).

21044554 is a wasteful number, since it uses less digits than its factorization.

21044554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10522279.

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

The square root of 21044554 is about 4587.4343592034. The cubic root of 21044554 is about 276.0873926849.

Adding to 21044554 its reverse (45544012), we get a palindrome (66588566).

The spelling of 21044554 in words is "twenty-one million, forty-four thousand, five hundred fifty-four".