21030308 has 12 divisors (see below), whose sum is σ = 39634140. Its totient is φ = 9706272.

The previous prime is 21030301. The next prime is 21030313. The reversal of 21030308 is 80303012.

It can be written as a sum of positive squares in 2 ways, for example, as 7795264 + 13235044 = 2792^2 + 3638^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202163 + ... + 202266.

It is an arithmetic number, because the mean of its divisors is an integer number (3302845).

Almost surely, 2^21030308 is an apocalyptic number.

It is an amenable number.

21030308 is a deficient number, since it is larger than the sum of its proper divisors (18603832).

21030308 is a wasteful number, since it uses less digits than its factorization.

21030308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404446 (or 404444 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21030308 is about 4585.8813765731. The cubic root of 21030308 is about 276.0250799866.

The spelling of 21030308 in words is "twenty-one million, thirty thousand, three hundred eight".