20778424 has 8 divisors (see below), whose sum is σ = 38959560. Its totient is φ = 10389208.

The previous prime is 20778391. The next prime is 20778449. The reversal of 20778424 is 42487702.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 20778424.

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 as a sum of consecutive naturals, namely, 1298644 + ... + 1298659.

It is an arithmetic number, because the mean of its divisors is an integer number (4869945).

Almost surely, 2^20778424 is an apocalyptic number.

It is an amenable number.

20778424 is a deficient number, since it is larger than the sum of its proper divisors (18181136).

20778424 is a wasteful number, since it uses less digits than its factorization.

20778424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2597309 (or 2597305 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 34.

The square root of 20778424 is about 4558.3356611816. The cubic root of 20778424 is about 274.9186492153.

It can be divided in two parts, 2077 and 8424, that added together give a palindrome (10501).

The spelling of 20778424 in words is "twenty million, seven hundred seventy-eight thousand, four hundred twenty-four".