21542130 has 24 divisors (see below), whose sum is σ = 56009772. Its totient is φ = 5744544.

The previous prime is 21542119. The next prime is 21542153. The reversal of 21542130 is 3124512.

21542130 is a `hidden beast` number, since 215 + 421 + 30 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21538881 + 3249 = 4641^2 + 57^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 119589 + ... + 119768.

Almost surely, 2^21542130 is an apocalyptic number.

21542130 is an abundant number, since it is smaller than the sum of its proper divisors (34467642).

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

21542130 is a wasteful number, since it uses less digits than its factorization.

21542130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239370 (or 239367 counting only the distinct ones).

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

The square root of 21542130 is about 4641.3500191216. The cubic root of 21542130 is about 278.2463957705.

Adding to 21542130 its reverse (3124512), we get a palindrome (24666642).

The spelling of 21542130 in words is "twenty-one million, five hundred forty-two thousand, one hundred thirty".