20398940064 has 144 divisors (see below), whose sum is σ = 59006787840. Its totient is φ = 6683212800.

The previous prime is 20398940063. The next prime is 20398940117. The reversal of 20398940064 is 46004989302.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×20398940064² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20398940063) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11596017 + ... + 11597775.

It is an arithmetic number, because the mean of its divisors is an integer number (409769360).

Almost surely, 2^20398940064 is an apocalyptic number.

20398940064 is a gapful number since it is divisible by the number (24) 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 20398940064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29503393920).

20398940064 is an abundant number, since it is smaller than the sum of its proper divisors (38607847776).

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

20398940064 is a wasteful number, since it uses less digits than its factorization.

20398940064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2443 (or 2432 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The spelling of 20398940064 in words is "twenty billion, three hundred ninety-eight million, nine hundred forty thousand, sixty-four".