21142530 has 24 divisors (see below), whose sum is σ = 54970812. Its totient is φ = 5637984.

The previous prime is 21142529. The next prime is 21142531. The reversal of 21142530 is 3524112.

21142530 is a `hidden beast` number, since 211 + 425 + 30 = 666.

It is an interprime number because it is at equal distance from previous prime (21142529) and next prime (21142531).

It can be written as a sum of positive squares in 2 ways, for example, as 20548089 + 594441 = 4533^2 + 771^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21142531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 117369 + ... + 117548.

Almost surely, 2^21142530 is an apocalyptic number.

21142530 is an abundant number, since it is smaller than the sum of its proper divisors (33828282).

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

21142530 is a wasteful number, since it uses less digits than its factorization.

21142530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234930 (or 234927 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21142530 is about 4598.1006948522. The cubic root of 21142530 is about 276.5151845705.

Adding to 21142530 its reverse (3524112), we get a palindrome (24666642).

The spelling of 21142530 in words is "twenty-one million, one hundred forty-two thousand, five hundred thirty".