21530337 has 16 divisors (see below), whose sum is σ = 30438912. Its totient is φ = 13512960.

The previous prime is 21530329. The next prime is 21530387. The reversal of 21530337 is 73303512.

It is not a de Polignac number, because 21530337 - 2³ = 21530329 is a prime.

It is a super-2 number, since 2×21530337² = 927110822667138, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21530387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 313 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (1902432).

Almost surely, 2^21530337 is an apocalyptic number.

It is an amenable number.

21530337 is a deficient number, since it is larger than the sum of its proper divisors (8908575).

21530337 is a wasteful number, since it uses less digits than its factorization.

21530337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6328.

The product of its (nonzero) digits is 1890, while the sum is 24.

The square root of 21530337 is about 4640.0794174238. The cubic root of 21530337 is about 278.1956122019.

Adding to 21530337 its reverse (73303512), we get a palindrome (94833849).

The spelling of 21530337 in words is "twenty-one million, five hundred thirty thousand, three hundred thirty-seven".