20779740 has 120 divisors (see below), whose sum is σ = 66350592. Its totient is φ = 5443200.

The previous prime is 20779739. The next prime is 20779751. The reversal of 20779740 is 4797702.

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 = 20779695 and 20779704.

It is a congruent number.

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 39 ways as a sum of consecutive naturals, for example, 163557 + ... + 163683.

Almost surely, 2^20779740 is an apocalyptic number.

20779740 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 20779740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33175296).

20779740 is an abundant number, since it is smaller than the sum of its proper divisors (45570852).

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

20779740 is a wasteful number, since it uses less digits than its factorization.

20779740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249 (or 238 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 36.

The square root of 20779740 is about 4558.4800098278. The cubic root of 20779740 is about 274.9244530771.

The spelling of 20779740 in words is "twenty million, seven hundred seventy-nine thousand, seven hundred forty".