20281641857 has 4 divisors (see below), whose sum is σ = 20353308720. Its totient is φ = 20209974996.

The previous prime is 20281641851. The next prime is 20281641911. The reversal of 20281641857 is 75814618202.

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 20281641857 - 2²⁶ = 20214532993 is a prime.

It is a super-2 number, since 2×20281641857² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20281641851) 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, 35833007 + ... + 35833572.

It is an arithmetic number, because the mean of its divisors is an integer number (5088327180).

Almost surely, 2^20281641857 is an apocalyptic number.

It is an amenable number.

20281641857 is a deficient number, since it is larger than the sum of its proper divisors (71666863).

20281641857 is an equidigital number, since it uses as much as digits as its factorization.

20281641857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71666862.

The product of its (nonzero) digits is 215040, while the sum is 44.

The spelling of 20281641857 in words is "twenty billion, two hundred eighty-one million, six hundred forty-one thousand, eight hundred fifty-seven".