20777984 has 44 divisors (see below), whose sum is σ = 42151824. Its totient is φ = 10235904.

The previous prime is 20777969. The next prime is 20777989. The reversal of 20777984 is 48977702.

It is not an unprimeable number, because it can be changed into a prime (20777989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105374 + ... + 105570.

It is an arithmetic number, because the mean of its divisors is an integer number (957996).

Almost surely, 2^20777984 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20777984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21075912).

20777984 is an abundant number, since it is smaller than the sum of its proper divisors (21373840).

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

20777984 is a wasteful number, since it uses less digits than its factorization.

20777984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320 (or 302 counting only the distinct ones).

The product of its (nonzero) digits is 197568, while the sum is 44.

The square root of 20777984 is about 4558.2873976966. The cubic root of 20777984 is about 274.9167086598.

The spelling of 20777984 in words is "twenty million, seven hundred seventy-seven thousand, nine hundred eighty-four".