21542064 has 20 divisors (see below), whose sum is σ = 55650456. Its totient is φ = 7180672.

The previous prime is 21542063. The next prime is 21542071. The reversal of 21542064 is 46024512.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21542063) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224349 + ... + 224444.

Almost surely, 2^21542064 is an apocalyptic number.

21542064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21542064 is an abundant number, since it is smaller than the sum of its proper divisors (34108392).

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

21542064 is a wasteful number, since it uses less digits than its factorization.

21542064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448804 (or 448798 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21542064 is about 4641.3429091159. The cubic root of 21542064 is about 278.2461116097.

Adding to 21542064 its reverse (46024512), we get a palindrome (67566576).

The spelling of 21542064 in words is "twenty-one million, five hundred forty-two thousand, sixty-four".