21023735 has 8 divisors (see below), whose sum is σ = 26042496. Its totient is φ = 16276320.

The previous prime is 21023731. The next prime is 21023741. The reversal of 21023735 is 53732012.

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

It is not a de Polignac number, because 21023735 - 2² = 21023731 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21023735.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023731) 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, 67664 + ... + 67973.

It is an arithmetic number, because the mean of its divisors is an integer number (3255312).

Almost surely, 2^21023735 is an apocalyptic number.

21023735 is a deficient number, since it is larger than the sum of its proper divisors (5018761).

21023735 is a wasteful number, since it uses less digits than its factorization.

21023735 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135673.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21023735 is about 4585.1646644368. The cubic root of 21023735 is about 275.9963198767.

Adding to 21023735 its reverse (53732012), we get a palindrome (74755747).

The spelling of 21023735 in words is "twenty-one million, twenty-three thousand, seven hundred thirty-five".