21757742 has 16 divisors (see below), whose sum is σ = 33530112. Its totient is φ = 10583160.

The previous prime is 21757733. The next prime is 21757783. The reversal of 21757742 is 24775712.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 36773 + ... + 37359.

It is an arithmetic number, because the mean of its divisors is an integer number (2095632).

Almost surely, 2^21757742 is an apocalyptic number.

21757742 is a deficient number, since it is larger than the sum of its proper divisors (11772370).

21757742 is a wasteful number, since it uses less digits than its factorization.

21757742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063.

The product of its digits is 27440, while the sum is 35.

The square root of 21757742 is about 4664.5194822189. The cubic root of 21757742 is about 279.1716248123.

The spelling of 21757742 in words is "twenty-one million, seven hundred fifty-seven thousand, seven hundred forty-two".