21545042 has 16 divisors (see below), whose sum is σ = 32796672. Its totient is φ = 10614240.

The previous prime is 21545039. The next prime is 21545047. The reversal of 21545042 is 24054512.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21544999 and 21545017.

It is not an unprimeable number, because it can be changed into a prime (21545047) 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, 68678 + ... + 68990.

It is an arithmetic number, because the mean of its divisors is an integer number (2049792).

Almost surely, 2^21545042 is an apocalyptic number.

21545042 is a deficient number, since it is larger than the sum of its proper divisors (11251630).

21545042 is a wasteful number, since it uses less digits than its factorization.

21545042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713.

The product of its (nonzero) digits is 1600, while the sum is 23.

The square root of 21545042 is about 4641.6637103521. The cubic root of 21545042 is about 278.2589327077.

Adding to 21545042 its reverse (24054512), we get a palindrome (45599554).

The spelling of 21545042 in words is "twenty-one million, five hundred forty-five thousand, forty-two".