16781632787 has 4 divisors (see below), whose sum is σ = 16865962800. Its totient is φ = 16697302776.

The previous prime is 16781632711. The next prime is 16781632811. The reversal of 16781632787 is 78723618761.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78723618761 = 24509 ⋅3212029.

It is a cyclic number.

It is not a de Polignac number, because 16781632787 - 2¹⁴ = 16781616403 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16781637787) 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, 42164708 + ... + 42165105.

It is an arithmetic number, because the mean of its divisors is an integer number (4216490700).

Almost surely, 2^16781632787 is an apocalyptic number.

16781632787 is a deficient number, since it is larger than the sum of its proper divisors (84330013).

16781632787 is an equidigital number, since it uses as much as digits as its factorization.

16781632787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84330012.

The product of its digits is 4741632, while the sum is 56.

The spelling of 16781632787 in words is "sixteen billion, seven hundred eighty-one million, six hundred thirty-two thousand, seven hundred eighty-seven".