21232515 has 16 divisors (see below), whose sum is σ = 34154496. Its totient is φ = 11263200.

The previous prime is 21232513. The next prime is 21232531. The reversal of 21232515 is 51523212.

It is not a de Polignac number, because 21232515 - 2¹ = 21232513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21232491 and 21232500.

It is not an unprimeable number, because it can be changed into a prime (21232511) 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, 841 + ... + 6570.

It is an arithmetic number, because the mean of its divisors is an integer number (2134656).

Almost surely, 2^21232515 is an apocalyptic number.

21232515 is a deficient number, since it is larger than the sum of its proper divisors (12921981).

21232515 is a wasteful number, since it uses less digits than its factorization.

21232515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7610.

The product of its digits is 600, while the sum is 21.

The square root of 21232515 is about 4607.8753238342. The cubic root of 21232515 is about 276.9069226391.

Adding to 21232515 its reverse (51523212), we get a palindrome (72755727).

The spelling of 21232515 in words is "twenty-one million, two hundred thirty-two thousand, five hundred fifteen".