21242045 has 8 divisors (see below), whose sum is σ = 27807840. Its totient is φ = 15448720.

The previous prime is 21241991. The next prime is 21242047. The reversal of 21242045 is 54024212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21242045 - 2¹⁴ = 21225661 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242047) 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, 193055 + ... + 193164.

It is an arithmetic number, because the mean of its divisors is an integer number (3475980).

Almost surely, 2^21242045 is an apocalyptic number.

It is an amenable number.

21242045 is a deficient number, since it is larger than the sum of its proper divisors (6565795).

21242045 is a wasteful number, since it uses less digits than its factorization.

21242045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386235.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21242045 is about 4608.9093069836. The cubic root of 21242045 is about 276.9483454012.

Adding to 21242045 its reverse (54024212), we get a palindrome (75266257).

The spelling of 21242045 in words is "twenty-one million, two hundred forty-two thousand, forty-five".