21552315 has 16 divisors (see below), whose sum is σ = 35416608. Its totient is φ = 11183616.

The previous prime is 21552283. The next prime is 21552317. The reversal of 21552315 is 51325512.

It is a happy number.

It is not a de Polignac number, because 21552315 - 2⁵ = 21552283 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21552317) 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, 18862 + ... + 19971.

It is an arithmetic number, because the mean of its divisors is an integer number (2213538).

Almost surely, 2^21552315 is an apocalyptic number.

21552315 is a deficient number, since it is larger than the sum of its proper divisors (13864293).

21552315 is a wasteful number, since it uses less digits than its factorization.

21552315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38878.

The product of its digits is 1500, while the sum is 24.

The square root of 21552315 is about 4642.4470917825. The cubic root of 21552315 is about 278.2902399808.

Adding to 21552315 its reverse (51325512), we get a palindrome (72877827).

The spelling of 21552315 in words is "twenty-one million, five hundred fifty-two thousand, three hundred fifteen".