21280030 has 16 divisors (see below), whose sum is σ = 39027744. Its totient is φ = 8351200.

The previous prime is 21280013. The next prime is 21280067. The reversal of 21280030 is 3008212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21279986 and 21280013.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19546 + ... + 20605.

It is an arithmetic number, because the mean of its divisors is an integer number (2439234).

Almost surely, 2^21280030 is an apocalyptic number.

21280030 is a deficient number, since it is larger than the sum of its proper divisors (17747714).

21280030 is a wasteful number, since it uses less digits than its factorization.

21280030 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40211.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21280030 is about 4613.0282895296. The cubic root of 21280030 is about 277.1133266695.

Adding to 21280030 its reverse (3008212), we get a palindrome (24288242).

The spelling of 21280030 in words is "twenty-one million, two hundred eighty thousand, thirty".