21552030 has 48 divisors (see below), whose sum is σ = 57348720. Its totient is φ = 5612544.

The previous prime is 21552007. The next prime is 21552031. The reversal of 21552030 is 3025512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21551994 and 21552012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552031) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1086 + ... + 6654.

It is an arithmetic number, because the mean of its divisors is an integer number (1194765).

Almost surely, 2^21552030 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21552030, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28674360).

21552030 is an abundant number, since it is smaller than the sum of its proper divisors (35796690).

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

21552030 is a wasteful number, since it uses less digits than its factorization.

21552030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5625 (or 5622 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21552030 is about 4642.4163966624. The cubic root of 21552030 is about 278.2890133056.

Adding to 21552030 its reverse (3025512), we get a palindrome (24577542).

The spelling of 21552030 in words is "twenty-one million, five hundred fifty-two thousand, thirty".