21013030 has 32 divisors (see below), whose sum is σ = 39896064. Its totient is φ = 7952736.

The previous prime is 21013021. The next prime is 21013043. The reversal of 21013030 is 3031012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21012998 and 21013016.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23247 + ... + 24133.

It is an arithmetic number, because the mean of its divisors is an integer number (1246752).

Almost surely, 2^21013030 is an apocalyptic number.

21013030 is a deficient number, since it is larger than the sum of its proper divisors (18883034).

21013030 is a wasteful number, since it uses less digits than its factorization.

21013030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21013030 is about 4583.9971640480. The cubic root of 21013030 is about 275.9494673992.

Adding to 21013030 its reverse (3031012), we get a palindrome (24044042).

The spelling of 21013030 in words is "twenty-one million, thirteen thousand, thirty".