20198321640 has 384 divisors, whose sum is σ = 79803360000. Its totient is φ = 4327686144.

The previous prime is 20198321623. The next prime is 20198321657. The reversal of 20198321640 is 4612389102.

20198321640 is a `hidden beast` number, since 2 + 0 + 1 + 9 + 8 + 3 + 2 + 1 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (20198321623) and next prime (20198321657).

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

It is a junction number, because it is equal to n+sod(n) for n = 20198321595 and 20198321604.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4642186 + ... + 4646534.

It is an arithmetic number, because the mean of its divisors is an integer number (207821250).

Almost surely, 2^20198321640 is an apocalyptic number.

20198321640 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 20198321640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39901680000).

20198321640 is an abundant number, since it is smaller than the sum of its proper divisors (59605038360).

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

20198321640 is a wasteful number, since it uses less digits than its factorization.

20198321640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4489 (or 4482 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The spelling of 20198321640 in words is "twenty billion, one hundred ninety-eight million, three hundred twenty-one thousand, six hundred forty".