21747135 has 32 divisors (see below), whose sum is σ = 35988480. Its totient is φ = 11207808.

The previous prime is 21747133. The next prime is 21747149. The reversal of 21747135 is 53174712.

It is not a de Polignac number, because 21747135 - 2¹ = 21747133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21747133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 76704 + ... + 76986.

It is an arithmetic number, because the mean of its divisors is an integer number (1124640).

Almost surely, 2^21747135 is an apocalyptic number.

21747135 is a deficient number, since it is larger than the sum of its proper divisors (14241345).

21747135 is a wasteful number, since it uses less digits than its factorization.

21747135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447.

The product of its digits is 5880, while the sum is 30.

The square root of 21747135 is about 4663.3823561874. The cubic root of 21747135 is about 279.1262516183.

The spelling of 21747135 in words is "twenty-one million, seven hundred forty-seven thousand, one hundred thirty-five".