20825841557 has 4 divisors (see below), whose sum is σ = 20831095296. Its totient is φ = 20820587820.

The previous prime is 20825841511. The next prime is 20825841563. The reversal of 20825841557 is 75514852802.

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 an emirpimes, since its reverse is a distinct semiprime: 75514852802 = 2 ⋅37757426401.

It is a cyclic number.

It is not a de Polignac number, because 20825841557 - 2⁸ = 20825841301 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 (20825441557) 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, 2620919 + ... + 2628852.

It is an arithmetic number, because the mean of its divisors is an integer number (5207773824).

Almost surely, 2^20825841557 is an apocalyptic number.

It is an amenable number.

20825841557 is a deficient number, since it is larger than the sum of its proper divisors (5253739).

20825841557 is an equidigital number, since it uses as much as digits as its factorization.

20825841557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5253738.

The product of its (nonzero) digits is 896000, while the sum is 47.

The spelling of 20825841557 in words is "twenty billion, eight hundred twenty-five million, eight hundred forty-one thousand, five hundred fifty-seven".