21213030 has 32 divisors (see below), whose sum is σ = 51422688. Its totient is φ = 5600000.

The previous prime is 21213029. The next prime is 21213041. The reversal of 21213030 is 3031212.

It is a happy number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21212997 and 21213015.

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, 471 + ... + 6530.

It is an arithmetic number, because the mean of its divisors is an integer number (1606959).

Almost surely, 2^21213030 is an apocalyptic number.

21213030 is an abundant number, since it is smaller than the sum of its proper divisors (30209658).

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

21213030 is a wasteful number, since it uses less digits than its factorization.

21213030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7112.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21213030 is about 4605.7605235183. The cubic root of 21213030 is about 276.8221912304.

Adding to 21213030 its reverse (3031212), we get a palindrome (24244242).

It can be divided in two parts, 2121 and 3030, that added together give a triangular number (5151 = T₁₀₁).

The spelling of 21213030 in words is "twenty-one million, two hundred thirteen thousand, thirty".