20532440391 has 4 divisors (see below), whose sum is σ = 27376587192. Its totient is φ = 13688293592.

The previous prime is 20532440381. The next prime is 20532440429. The reversal of 20532440391 is 19304423502.

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

It is a cyclic number.

It is not a de Polignac number, because 20532440391 - 2¹⁴ = 20532424007 is a prime.

It is a super-2 number, since 2×20532440391² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20532440321) 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, 3422073396 + ... + 3422073401.

It is an arithmetic number, because the mean of its divisors is an integer number (6844146798).

Almost surely, 2^20532440391 is an apocalyptic number.

20532440391 is a deficient number, since it is larger than the sum of its proper divisors (6844146801).

20532440391 is an equidigital number, since it uses as much as digits as its factorization.

20532440391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6844146800.

The product of its (nonzero) digits is 25920, while the sum is 33.

Adding to 20532440391 its reverse (19304423502), we get a palindrome (39836863893).

The spelling of 20532440391 in words is "twenty billion, five hundred thirty-two million, four hundred forty thousand, three hundred ninety-one".