21704757 has 8 divisors (see below), whose sum is σ = 28964160. Its totient is φ = 14457600.

The previous prime is 21704737. The next prime is 21704791. The reversal of 21704757 is 75740712.

It is a happy number.

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

It is not a de Polignac number, because 21704757 - 2⁶ = 21704693 is a prime.

It is a super-3 number, since 3×21704757³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21704737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2544 + ... + 7062.

It is an arithmetic number, because the mean of its divisors is an integer number (3620520).

Almost surely, 2^21704757 is an apocalyptic number.

It is an amenable number.

21704757 is a deficient number, since it is larger than the sum of its proper divisors (7259403).

21704757 is a wasteful number, since it uses less digits than its factorization.

21704757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6123.

The product of its (nonzero) digits is 13720, while the sum is 33.

The square root of 21704757 is about 4658.8364427183. The cubic root of 21704757 is about 278.9448253583.

The spelling of 21704757 in words is "twenty-one million, seven hundred four thousand, seven hundred fifty-seven".