816653643391 has 8 divisors (see below), whose sum is σ = 821881075680. Its totient is φ = 811426538208.

The previous prime is 816653643349. The next prime is 816653643397. The reversal of 816653643391 is 193346356618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 816653643391 - 2⁹ = 816653642879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816653643397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6741045 + ... + 6861121.

It is an arithmetic number, because the mean of its divisors is an integer number (102735134460).

Almost surely, 2^816653643391 is an apocalyptic number.

816653643391 is a deficient number, since it is larger than the sum of its proper divisors (5227432289).

816653643391 is a wasteful number, since it uses less digits than its factorization.

816653643391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163553.

The product of its digits is 8398080, while the sum is 55.

The spelling of 816653643391 in words is "eight hundred sixteen billion, six hundred fifty-three million, six hundred forty-three thousand, three hundred ninety-one".