20019857531 has 4 divisors (see below), whose sum is σ = 20020317072. Its totient is φ = 20019397992.

The previous prime is 20019857527. The next prime is 20019857551. The reversal of 20019857531 is 13575891002.

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 20019857531 - 2² = 20019857527 is a prime.

It is a super-2 number, since 2×20019857531² (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 (20019857551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156671 + ... + 254136.

It is an arithmetic number, because the mean of its divisors is an integer number (5005079268).

Almost surely, 2^20019857531 is an apocalyptic number.

20019857531 is a deficient number, since it is larger than the sum of its proper divisors (459541).

20019857531 is an equidigital number, since it uses as much as digits as its factorization.

20019857531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 459540.

The product of its (nonzero) digits is 75600, while the sum is 41.

The spelling of 20019857531 in words is "twenty billion, nineteen million, eight hundred fifty-seven thousand, five hundred thirty-one".