21006652 has 6 divisors (see below), whose sum is σ = 36761648. Its totient is φ = 10503324.

The previous prime is 21006641. The next prime is 21006673. The reversal of 21006652 is 25660012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625828 + ... + 2625835.

Almost surely, 2^21006652 is an apocalyptic number.

It is an amenable number.

21006652 is a deficient number, since it is larger than the sum of its proper divisors (15754996).

21006652 is a wasteful number, since it uses less digits than its factorization.

21006652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5251667 (or 5251665 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21006652 is about 4583.3014301920. The cubic root of 21006652 is about 275.9215452987.

Adding to 21006652 its reverse (25660012), we get a palindrome (46666664).

The spelling of 21006652 in words is "twenty-one million, six thousand, six hundred fifty-two".