21030564 has 24 divisors (see below), whose sum is σ = 51958368. Its totient is φ = 6597760.

The previous prime is 21030557. The next prime is 21030589. The reversal of 21030564 is 46503012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21030564.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51342 + ... + 51749.

It is an arithmetic number, because the mean of its divisors is an integer number (2164932).

Almost surely, 2^21030564 is an apocalyptic number.

It is an amenable number.

21030564 is an abundant number, since it is smaller than the sum of its proper divisors (30927804).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21030564 is a wasteful number, since it uses less digits than its factorization.

21030564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103115 (or 103113 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21030564 is about 4585.9092882437. The cubic root of 21030564 is about 276.0261999913.

Adding to 21030564 its reverse (46503012), we get a palindrome (67533576).

The spelling of 21030564 in words is "twenty-one million, thirty thousand, five hundred sixty-four".