21525742 has 16 divisors (see below), whose sum is σ = 36980352. Its totient is φ = 9205560.

The previous prime is 21525733. The next prime is 21525767. The reversal of 21525742 is 24752512.

It is a self number, because there is not a number n which added to its sum of digits gives 21525742.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 6517 + ... + 9247.

It is an arithmetic number, because the mean of its divisors is an integer number (2311272).

Almost surely, 2^21525742 is an apocalyptic number.

21525742 is a deficient number, since it is larger than the sum of its proper divisors (15454610).

21525742 is a wasteful number, since it uses less digits than its factorization.

21525742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3303.

The product of its digits is 5600, while the sum is 28.

The square root of 21525742 is about 4639.5842486154. The cubic root of 21525742 is about 278.1758199774.

The spelling of 21525742 in words is "twenty-one million, five hundred twenty-five thousand, seven hundred forty-two".