21342544 has 10 divisors (see below), whose sum is σ = 41351210. Its totient is φ = 10671264.

The previous prime is 21342533. The next prime is 21342553. The reversal of 21342544 is 44524312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13987600 + 7354944 = 3740^2 + 2712^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 666939 + ... + 666970.

It is an arithmetic number, because the mean of its divisors is an integer number (4135121).

Almost surely, 2^21342544 is an apocalyptic number.

It is an amenable number.

21342544 is a deficient number, since it is larger than the sum of its proper divisors (20008666).

21342544 is a wasteful number, since it uses less digits than its factorization.

21342544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333917 (or 1333911 counting only the distinct ones).

The product of its digits is 3840, while the sum is 25.

The square root of 21342544 is about 4619.7991298324. The cubic root of 21342544 is about 277.3844184946.

Adding to 21342544 its reverse (44524312), we get a palindrome (65866856).

The spelling of 21342544 in words is "twenty-one million, three hundred forty-two thousand, five hundred forty-four".