20531443397 has 4 divisors (see below), whose sum is σ = 20573259456. Its totient is φ = 20489627340.

The previous prime is 20531443381. The next prime is 20531443411. The reversal of 20531443397 is 79334413502.

It is a happy number.

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 20531443397 - 2⁴ = 20531443381 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 (20531443367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20907293 + ... + 20908274.

It is an arithmetic number, because the mean of its divisors is an integer number (5143314864).

Almost surely, 2^20531443397 is an apocalyptic number.

It is an amenable number.

20531443397 is a deficient number, since it is larger than the sum of its proper divisors (41816059).

20531443397 is an equidigital number, since it uses as much as digits as its factorization.

20531443397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41816058.

The product of its (nonzero) digits is 272160, while the sum is 41.

Adding to 20531443397 its reverse (79334413502), we get a palindrome (99865856899).

The spelling of 20531443397 in words is "twenty billion, five hundred thirty-one million, four hundred forty-three thousand, three hundred ninety-seven".