21040653 has 8 divisors (see below), whose sum is σ = 29274048. Its totient is φ = 13417184.

The previous prime is 21040651. The next prime is 21040673. The reversal of 21040653 is 35604012.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21040653 - 2¹ = 21040651 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040651) 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, 152400 + ... + 152537.

It is an arithmetic number, because the mean of its divisors is an integer number (3659256).

Almost surely, 2^21040653 is an apocalyptic number.

21040653 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21040653 is a deficient number, since it is larger than the sum of its proper divisors (8233395).

21040653 is a wasteful number, since it uses less digits than its factorization.

21040653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304963.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21040653 is about 4587.0091563022. The cubic root of 21040653 is about 276.0703323174.

Adding to 21040653 its reverse (35604012), we get a palindrome (56644665).

The spelling of 21040653 in words is "twenty-one million, forty thousand, six hundred fifty-three".