816065621 has 4 divisors (see below), whose sum is σ = 932646432. Its totient is φ = 699484812.

The previous prime is 816065617. The next prime is 816065623. The reversal of 816065621 is 126560618.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 816065621 - 2² = 816065617 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 (816065623) 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, 58290395 + ... + 58290408.

It is an arithmetic number, because the mean of its divisors is an integer number (233161608).

Almost surely, 2^816065621 is an apocalyptic number.

It is an amenable number.

816065621 is a deficient number, since it is larger than the sum of its proper divisors (116580811).

816065621 is a wasteful number, since it uses less digits than its factorization.

816065621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116580810.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 816065621 is about 28566.8622883228. The cubic root of 816065621 is about 934.4907942548.

The spelling of 816065621 in words is "eight hundred sixteen million, sixty-five thousand, six hundred twenty-one".