16778920 has 16 divisors (see below), whose sum is σ = 37752660. Its totient is φ = 6711552.

The previous prime is 16778917. The next prime is 16778929. The reversal of 16778920 is 2987761.

It can be written as a sum of positive squares in 2 ways, for example, as 14699556 + 2079364 = 3834^2 + 1442^2 .

It is a Harshad number since it is a multiple of its sum of digits (40), and also a Moran number because the ratio is a prime number: 419473 = 16778920 / (1 + 6 + 7 + 7 + 8 + 9 + 2 + 0).

It is not an unprimeable number, because it can be changed into a prime (16778929) 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, 209697 + ... + 209776.

Almost surely, 2^16778920 is an apocalyptic number.

16778920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16778920 is an abundant number, since it is smaller than the sum of its proper divisors (20973740).

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

16778920 is a wasteful number, since it uses less digits than its factorization.

16778920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419484 (or 419480 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 16778920 is about 4096.2080025311. The cubic root of 16778920 is about 256.0086666988.

The spelling of 16778920 in words is "sixteen million, seven hundred seventy-eight thousand, nine hundred twenty".