20425231243531 has 4 divisors (see below), whose sum is σ = 20506606667064. Its totient is φ = 20343855820000.

The previous prime is 20425231243507. The next prime is 20425231243537. The reversal of 20425231243531 is 13534213252402.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20425231243531 is a prime.

It is a super-2 number, since 2×20425231243531² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20425231243537) 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, 40687711390 + ... + 40687711891.

It is an arithmetic number, because the mean of its divisors is an integer number (5126651666766).

Almost surely, 2^{20425231243531} is an apocalyptic number.

20425231243531 is a deficient number, since it is larger than the sum of its proper divisors (81375423533).

20425231243531 is an equidigital number, since it uses as much as digits as its factorization.

20425231243531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81375423532.

The product of its (nonzero) digits is 172800, while the sum is 37.

Adding to 20425231243531 its reverse (13534213252402), we get a palindrome (33959444495933).

The spelling of 20425231243531 in words is "twenty trillion, four hundred twenty-five billion, two hundred thirty-one million, two hundred forty-three thousand, five hundred thirty-one".