20397541 has 4 divisors (see below), whose sum is σ = 20895084. Its totient is φ = 19900000.

The previous prime is 20397529. The next prime is 20397551. The reversal of 20397541 is 14579302.

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 3348900 + 17048641 = 1830^2 + 4129^2 .

It is a cyclic number.

It is not a de Polignac number, because 20397541 - 2¹⁷ = 20266469 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397511) 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, 248710 + ... + 248791.

It is an arithmetic number, because the mean of its divisors is an integer number (5223771).

Almost surely, 2^20397541 is an apocalyptic number.

It is an amenable number.

20397541 is a deficient number, since it is larger than the sum of its proper divisors (497543).

20397541 is an equidigital number, since it uses as much as digits as its factorization.

20397541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497542.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20397541 is about 4516.3636921754. The cubic root of 20397541 is about 273.2284624790.

The spelling of 20397541 in words is "twenty million, three hundred ninety-seven thousand, five hundred forty-one".