21242654 has 4 divisors (see below), whose sum is σ = 31863984. Its totient is φ = 10621326.

The previous prime is 21242651. The next prime is 21242659. The reversal of 21242654 is 45624212.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5310662 + ... + 5310665.

It is an arithmetic number, because the mean of its divisors is an integer number (7965996).

Almost surely, 2^21242654 is an apocalyptic number.

21242654 is a deficient number, since it is larger than the sum of its proper divisors (10621330).

21242654 is a wasteful number, since it uses less digits than its factorization.

21242654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10621329.

The product of its digits is 3840, while the sum is 26.

The square root of 21242654 is about 4608.9753742019. The cubic root of 21242654 is about 276.9509920379.

Adding to 21242654 its reverse (45624212), we get a palindrome (66866866).

The spelling of 21242654 in words is "twenty-one million, two hundred forty-two thousand, six hundred fifty-four".