20749541 has 4 divisors (see below), whose sum is σ = 20955084. Its totient is φ = 20544000.

The previous prime is 20749523. The next prime is 20749543. The reversal of 20749541 is 14594702.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8352100 + 12397441 = 2890^2 + 3521^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20749541 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20749498 and 20749507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20749543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102620 + ... + 102821.

It is an arithmetic number, because the mean of its divisors is an integer number (5238771).

Almost surely, 2^20749541 is an apocalyptic number.

It is an amenable number.

20749541 is a deficient number, since it is larger than the sum of its proper divisors (205543).

20749541 is a wasteful number, since it uses less digits than its factorization.

20749541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205542.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 20749541 is about 4555.1664074982. The cubic root of 20749541 is about 274.7912068036.

The spelling of 20749541 in words is "twenty million, seven hundred forty-nine thousand, five hundred forty-one".