20979981000 has 384 divisors, whose sum is σ = 78445635840. Its totient is φ = 5014656000.

The previous prime is 20979980929. The next prime is 20979981031. The reversal of 20979981000 is 18997902.

It is a super-2 number, since 2×20979981000² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7225549 + ... + 7228451.

It is an arithmetic number, because the mean of its divisors is an integer number (204285510).

Almost surely, 2^20979981000 is an apocalyptic number.

20979981000 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 20979981000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39222817920).

20979981000 is an abundant number, since it is smaller than the sum of its proper divisors (57465654840).

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

20979981000 is a wasteful number, since it uses less digits than its factorization.

20979981000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3014 (or 2997 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The spelling of 20979981000 in words is "twenty billion, nine hundred seventy-nine million, nine hundred eighty-one thousand".