20531237 has 4 divisors (see below), whose sum is σ = 20688096. Its totient is φ = 20374380.

The previous prime is 20531219. The next prime is 20531243. The reversal of 20531237 is 73213502.

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.

It is a cyclic number.

It is not a de Polignac number, because 20531237 - 2¹⁴ = 20514853 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 (20531297) 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, 78233 + ... + 78494.

It is an arithmetic number, because the mean of its divisors is an integer number (5172024).

Almost surely, 2^20531237 is an apocalyptic number.

It is an amenable number.

20531237 is a deficient number, since it is larger than the sum of its proper divisors (156859).

20531237 is a wasteful number, since it uses less digits than its factorization.

20531237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156858.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 20531237 is about 4531.1408055809. The cubic root of 20531237 is about 273.8241230165.

Adding to 20531237 its reverse (73213502), we get a palindrome (93744739).

The spelling of 20531237 in words is "twenty million, five hundred thirty-one thousand, two hundred thirty-seven".