20745638 has 8 divisors (see below), whose sum is σ = 31231632. Its totient is φ = 10335096.

The previous prime is 20745629. The next prime is 20745649. The reversal of 20745638 is 83654702.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 20745598 and 20745607.

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 3 ways as a sum of consecutive naturals, for example, 18170 + ... + 19277.

It is an arithmetic number, because the mean of its divisors is an integer number (3903954).

Almost surely, 2^20745638 is an apocalyptic number.

20745638 is a deficient number, since it is larger than the sum of its proper divisors (10485994).

20745638 is a wasteful number, since it uses less digits than its factorization.

20745638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37726.

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 20745638 is about 4554.7379727049. The cubic root of 20745638 is about 274.7739762644.

The spelling of 20745638 in words is "twenty million, seven hundred forty-five thousand, six hundred thirty-eight".