21903030 has 24 divisors (see below), whose sum is σ = 56948112. Its totient is φ = 5840784.

The previous prime is 21903017. The next prime is 21903031. The reversal of 21903030 is 3030912.

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

21903030 is a modest number, since divided by 3030 gives 2190 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21902994 and 21903012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21903031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 121594 + ... + 121773.

It is an arithmetic number, because the mean of its divisors is an integer number (2372838).

Almost surely, 2^21903030 is an apocalyptic number.

21903030 is an abundant number, since it is smaller than the sum of its proper divisors (35045082).

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

21903030 is a wasteful number, since it uses less digits than its factorization.

21903030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243380 (or 243377 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 18.

The square root of 21903030 is about 4680.0673072083. The cubic root of 21903030 is about 279.7916392054.

Adding to 21903030 its reverse (3030912), we get a palindrome (24933942).

The spelling of 21903030 in words is "twenty-one million, nine hundred three thousand, thirty".