20779551520 has 576 divisors, whose sum is σ = 66458206080. Its totient is φ = 6063095808.

The previous prime is 20779551487. The next prime is 20779551599. The reversal of 20779551520 is 2515597702.

It is a happy number.

It is a super-2 number, since 2×20779551520² (a number of 21 digits) contains 22 as substring.

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, 116086791 + ... + 116086969.

It is an arithmetic number, because the mean of its divisors is an integer number (115378830).

Almost surely, 2^20779551520 is an apocalyptic number.

20779551520 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 20779551520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33229103040).

20779551520 is an abundant number, since it is smaller than the sum of its proper divisors (45678654560).

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

20779551520 is a wasteful number, since it uses less digits than its factorization.

20779551520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 220500, while the sum is 43.

The spelling of 20779551520 in words is "twenty billion, seven hundred seventy-nine million, five hundred fifty-one thousand, five hundred twenty".