20012857920 has 588 divisors, whose sum is σ = 78647536380. Its totient is φ = 4844759040.

The previous prime is 20012857913. The next prime is 20012857927. The reversal of 20012857920 is 2975821002.

It is an interprime number because it is at equal distance from previous prime (20012857913) and next prime (20012857927).

It can be written as a sum of positive squares in 2 ways, for example, as 4747761216 + 15265096704 = 68904^2 + 123552^2 .

It is a super-2 number, since 2×20012857920² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20012857927) 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 83 ways as a sum of consecutive naturals, for example, 28226526 + ... + 28227234.

Almost surely, 2^20012857920 is an apocalyptic number.

20012857920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20012857920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39323768190).

20012857920 is an abundant number, since it is smaller than the sum of its proper divisors (58634678460).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20012857920 is an equidigital number, since it uses as much as digits as its factorization.

20012857920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 766 (or 730 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The spelling of 20012857920 in words is "twenty billion, twelve million, eight hundred fifty-seven thousand, nine hundred twenty".