21030515 has 8 divisors (see below), whose sum is σ = 27530928. Its totient is φ = 15294880.

The previous prime is 21030469. The next prime is 21030551. The reversal of 21030515 is 51503012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21030515 - 2¹² = 21026419 is a prime.

It is a super-2 number, since 2×21030515² = 884565122330450, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21030493 and 21030502.

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, 191132 + ... + 191241.

It is an arithmetic number, because the mean of its divisors is an integer number (3441366).

Almost surely, 2^21030515 is an apocalyptic number.

21030515 is a deficient number, since it is larger than the sum of its proper divisors (6500413).

21030515 is a wasteful number, since it uses less digits than its factorization.

21030515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382389.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21030515 is about 4585.9039457887. The cubic root of 21030515 is about 276.0259856161.

Adding to 21030515 its reverse (51503012), we get a palindrome (72533527).

The spelling of 21030515 in words is "twenty-one million, thirty thousand, five hundred fifteen".