21798315 has 96 divisors (see below), whose sum is σ = 49061376. Its totient is φ = 9020160.

The previous prime is 21798313. The next prime is 21798323. The reversal of 21798315 is 51389712.

It is not a de Polignac number, because 21798315 - 2¹ = 21798313 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21798315.

It is not an unprimeable number, because it can be changed into a prime (21798313) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 93439 + ... + 93671.

It is an arithmetic number, because the mean of its divisors is an integer number (511056).

Almost surely, 2^21798315 is an apocalyptic number.

21798315 is an abundant number, since it is smaller than the sum of its proper divisors (27263061).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21798315 is a wasteful number, since it uses less digits than its factorization.

21798315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271 (or 259 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21798315 is about 4668.8665648099. The cubic root of 21798315 is about 279.3450465612.

The spelling of 21798315 in words is "twenty-one million, seven hundred ninety-eight thousand, three hundred fifteen".