21445442 has 16 divisors (see below), whose sum is σ = 33989760. Its totient is φ = 10131408.

The previous prime is 21445441. The next prime is 21445451. The reversal of 21445442 is 24454412.

It is not an unprimeable number, because it can be changed into a prime (21445441) 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, 1208 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (2124360).

Almost surely, 2^21445442 is an apocalyptic number.

21445442 is a deficient number, since it is larger than the sum of its proper divisors (12544318).

21445442 is a wasteful number, since it uses less digits than its factorization.

21445442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7945.

The product of its digits is 5120, while the sum is 26.

The square root of 21445442 is about 4630.9223703275. The cubic root of 21445442 is about 277.8294849995.

Adding to 21445442 its reverse (24454412), we get a palindrome (45899854).

The spelling of 21445442 in words is "twenty-one million, four hundred forty-five thousand, four hundred forty-two".