21242735 has 8 divisors (see below), whose sum is σ = 25519536. Its totient is φ = 16975360.

The previous prime is 21242729. The next prime is 21242747. The reversal of 21242735 is 53724212.

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

It is not a de Polignac number, because 21242735 - 2⁸ = 21242479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4340 + ... + 7830.

It is an arithmetic number, because the mean of its divisors is an integer number (3189942).

Almost surely, 2^21242735 is an apocalyptic number.

21242735 is a deficient number, since it is larger than the sum of its proper divisors (4276801).

21242735 is a wasteful number, since it uses less digits than its factorization.

21242735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4713.

The product of its digits is 3360, while the sum is 26.

The square root of 21242735 is about 4608.9841613961. The cubic root of 21242735 is about 276.9513440499.

Adding to 21242735 its reverse (53724212), we get a palindrome (74966947).

The spelling of 21242735 in words is "twenty-one million, two hundred forty-two thousand, seven hundred thirty-five".