21054573 has 10 divisors (see below), whose sum is σ = 31452014. Its totient is φ = 14036328.

The previous prime is 21054569. The next prime is 21054601. The reversal of 21054573 is 37545012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 10673289 + 10381284 = 3267^2 + 3222^2 .

It is not a de Polignac number, because 21054573 - 2² = 21054569 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054533) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 129886 + ... + 130047.

Almost surely, 2^21054573 is an apocalyptic number.

It is an amenable number.

21054573 is a deficient number, since it is larger than the sum of its proper divisors (10397441).

21054573 is an equidigital number, since it uses as much as digits as its factorization.

21054573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259945 (or 259936 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 21054573 is about 4588.5262339884. The cubic root of 21054573 is about 276.1311994379.

Adding to 21054573 its reverse (37545012), we get a palindrome (58599585).

The spelling of 21054573 in words is "twenty-one million, fifty-four thousand, five hundred seventy-three".