21315430 has 16 divisors (see below), whose sum is σ = 38445264. Its totient is φ = 8508960.

The previous prime is 21315421. The next prime is 21315439. The reversal of 21315430 is 3451312.

It is an interprime number because it is at equal distance from previous prime (21315421) and next prime (21315439).

It is a junction number, because it is equal to n+sod(n) for n = 21315398 and 21315407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315439) 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, 3844 + ... + 7576.

It is an arithmetic number, because the mean of its divisors is an integer number (2402829).

Almost surely, 2^21315430 is an apocalyptic number.

21315430 is a deficient number, since it is larger than the sum of its proper divisors (17129834).

21315430 is a wasteful number, since it uses less digits than its factorization.

21315430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4311.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21315430 is about 4616.8636540405. The cubic root of 21315430 is about 277.2669037892.

Adding to 21315430 its reverse (3451312), we get a palindrome (24766742).

The spelling of 21315430 in words is "twenty-one million, three hundred fifteen thousand, four hundred thirty".