21220604 has 6 divisors (see below), whose sum is σ = 37136064. Its totient is φ = 10610300.

The previous prime is 21220601. The next prime is 21220613. The reversal of 21220604 is 40602212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2652572 + ... + 2652579.

It is an arithmetic number, because the mean of its divisors is an integer number (6189344).

Almost surely, 2^21220604 is an apocalyptic number.

It is an amenable number.

21220604 is a deficient number, since it is larger than the sum of its proper divisors (15915460).

21220604 is a wasteful number, since it uses less digits than its factorization.

21220604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5305155 (or 5305153 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21220604 is about 4606.5826813377. The cubic root of 21220604 is about 276.8551332759.

Adding to 21220604 its reverse (40602212), we get a palindrome (61822816).

The spelling of 21220604 in words is "twenty-one million, two hundred twenty thousand, six hundred four".