20506237 has 4 divisors (see below), whose sum is σ = 20516416. Its totient is φ = 20496060.

The previous prime is 20506201. The next prime is 20506243. The reversal of 20506237 is 73260502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20506237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20506247) 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, 939 + ... + 6472.

It is an arithmetic number, because the mean of its divisors is an integer number (5129104).

Almost surely, 2^20506237 is an apocalyptic number.

It is an amenable number.

20506237 is a deficient number, since it is larger than the sum of its proper divisors (10179).

20506237 is an equidigital number, since it uses as much as digits as its factorization.

20506237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10178.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 20506237 is about 4528.3812781169. The cubic root of 20506237 is about 273.7129366083.

Adding to 20506237 its reverse (73260502), we get a palindrome (93766739).

The spelling of 20506237 in words is "twenty million, five hundred six thousand, two hundred thirty-seven".