21671753 has 16 divisors (see below), whose sum is σ = 23794560. Its totient is φ = 19658496.

The previous prime is 21671743. The next prime is 21671791. The reversal of 21671753 is 35717612.

It is a cyclic number.

It is not a de Polignac number, because 21671753 - 2⁴ = 21671737 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21671743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60188 + ... + 60546.

It is an arithmetic number, because the mean of its divisors is an integer number (1487160).

Almost surely, 2^21671753 is an apocalyptic number.

It is an amenable number.

21671753 is a deficient number, since it is larger than the sum of its proper divisors (2122807).

21671753 is a wasteful number, since it uses less digits than its factorization.

21671753 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496.

The product of its digits is 8820, while the sum is 32.

The square root of 21671753 is about 4655.2930090382. The cubic root of 21671753 is about 278.8033668861.

The spelling of 21671753 in words is "twenty-one million, six hundred seventy-one thousand, seven hundred fifty-three".