20641979904 has 720 divisors, whose sum is σ = 74183720688. Its totient is φ = 5053612032.

The previous prime is 20641979879. The next prime is 20641979909. The reversal of 20641979904 is 40997914602.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20641979909) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 282766812 + ... + 282766884.

Almost surely, 2^20641979904 is an apocalyptic number.

20641979904 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 20641979904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37091860344).

20641979904 is an abundant number, since it is smaller than the sum of its proper divisors (53541740784).

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

20641979904 is a wasteful number, since it uses less digits than its factorization.

20641979904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 51.

The spelling of 20641979904 in words is "twenty billion, six hundred forty-one million, nine hundred seventy-nine thousand, nine hundred four".