16781403442 has 4 divisors (see below), whose sum is σ = 25172105166. Its totient is φ = 8390701720.

The previous prime is 16781403437. The next prime is 16781403449. The reversal of 16781403442 is 24430418761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24430418761 = 7 ⋅3490059823.

It can be written as a sum of positive squares in only one way, i.e., 16659323041 + 122080401 = 129071^2 + 11049^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 16781403395 and 16781403404.

It is not an unprimeable number, because it can be changed into a prime (16781403449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4195350859 + ... + 4195350862.

Almost surely, 2^16781403442 is an apocalyptic number.

16781403442 is a deficient number, since it is larger than the sum of its proper divisors (8390701724).

16781403442 is an equidigital number, since it uses as much as digits as its factorization.

16781403442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8390701723.

The product of its (nonzero) digits is 129024, while the sum is 40.

The spelling of 16781403442 in words is "sixteen billion, seven hundred eighty-one million, four hundred three thousand, four hundred forty-two".