21315502 has 8 divisors (see below), whose sum is σ = 34432776. Its totient is φ = 9837912.

The previous prime is 21315491. The next prime is 21315509. The reversal of 21315502 is 20551312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21315502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 409888 + ... + 409939.

It is an arithmetic number, because the mean of its divisors is an integer number (4304097).

Almost surely, 2^21315502 is an apocalyptic number.

21315502 is a deficient number, since it is larger than the sum of its proper divisors (13117274).

21315502 is a wasteful number, since it uses less digits than its factorization.

21315502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819842.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21315502 is about 4616.8714515351. The cubic root of 21315502 is about 277.2672159761.

Adding to 21315502 its reverse (20551312), we get a palindrome (41866814).

The spelling of 21315502 in words is "twenty-one million, three hundred fifteen thousand, five hundred two".