21004545 has 8 divisors (see below), whose sum is σ = 33607296. Its totient is φ = 11202416.

The previous prime is 21004541. The next prime is 21004547. The reversal of 21004545 is 54540012.

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

It is a cyclic number.

It is not a de Polignac number, because 21004545 - 2² = 21004541 is a prime.

21004545 is a modest number, since divided by 4545 gives 2100 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21004541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 700137 + ... + 700166.

It is an arithmetic number, because the mean of its divisors is an integer number (4200912).

Almost surely, 2^21004545 is an apocalyptic number.

It is an amenable number.

21004545 is a deficient number, since it is larger than the sum of its proper divisors (12602751).

21004545 is a wasteful number, since it uses less digits than its factorization.

21004545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400311.

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 21004545 is about 4583.0715682826. The cubic root of 21004545 is about 275.9123198696.

Adding to 21004545 its reverse (54540012), we get a palindrome (75544557).

The spelling of 21004545 in words is "twenty-one million, four thousand, five hundred forty-five".