21553030 has 16 divisors (see below), whose sum is σ = 40837680. Its totient is φ = 8167392.

The previous prime is 21553009. The next prime is 21553039. The reversal of 21553030 is 3035512.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a junction number, because it is equal to n+sod(n) for n = 21552989 and 21553007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21553039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56529 + ... + 56908.

It is an arithmetic number, because the mean of its divisors is an integer number (2552355).

Almost surely, 2^21553030 is an apocalyptic number.

21553030 is a deficient number, since it is larger than the sum of its proper divisors (19284650).

21553030 is a wasteful number, since it uses less digits than its factorization.

21553030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113463.

The product of its (nonzero) digits is 450, while the sum is 19.

The square root of 21553030 is about 4642.5240979450. The cubic root of 21553030 is about 278.2933173814.

Adding to 21553030 its reverse (3035512), we get a palindrome (24588542).

The spelling of 21553030 in words is "twenty-one million, five hundred fifty-three thousand, thirty".