21315948 has 24 divisors (see below), whose sum is σ = 52355520. Its totient is φ = 6731280.

The previous prime is 21315947. The next prime is 21315961. The reversal of 21315948 is 84951312.

It is not an unprimeable number, because it can be changed into a prime (21315947) 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, 46518 + ... + 46973.

It is an arithmetic number, because the mean of its divisors is an integer number (2181480).

Almost surely, 2^21315948 is an apocalyptic number.

It is an amenable number.

21315948 is an abundant number, since it is smaller than the sum of its proper divisors (31039572).

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

21315948 is a wasteful number, since it uses less digits than its factorization.

21315948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93517 (or 93515 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 21315948 is about 4616.9197523890. The cubic root of 21315948 is about 277.2691497849.

It can be divided in two parts, 213 and 15948, that added together give a palindrome (16161).

The spelling of 21315948 in words is "twenty-one million, three hundred fifteen thousand, nine hundred forty-eight".