21530410 has 16 divisors (see below), whose sum is σ = 42278112. Its totient is φ = 7829200.

The previous prime is 21530393. The next prime is 21530413. The reversal of 21530410 is 1403512.

It is not an unprimeable number, because it can be changed into a prime (21530413) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97756 + ... + 97975.

It is an arithmetic number, because the mean of its divisors is an integer number (2642382).

Almost surely, 2^21530410 is an apocalyptic number.

21530410 is a deficient number, since it is larger than the sum of its proper divisors (20747702).

21530410 is a wasteful number, since it uses less digits than its factorization.

21530410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195749.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21530410 is about 4640.0872836618. The cubic root of 21530410 is about 278.1959266149.

Adding to 21530410 its reverse (1403512), we get a palindrome (22933922).

It can be divided in two parts, 215 and 30410, that added together give a square (30625 = 175²).

The spelling of 21530410 in words is "twenty-one million, five hundred thirty thousand, four hundred ten".