820651 has 4 divisors (see below), whose sum is σ = 883792. Its totient is φ = 757512.

The previous prime is 820649. The next prime is 820657. The reversal of 820651 is 156028.

It is a happy number.

820651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 820651 - 2¹ = 820649 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (820657) 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, 31551 + ... + 31576.

It is an arithmetic number, because the mean of its divisors is an integer number (220948).

2⁸²⁰⁶⁵¹ is an apocalyptic number.

820651 is a deficient number, since it is larger than the sum of its proper divisors (63141).

820651 is a wasteful number, since it uses less digits than its factorization.

820651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63140.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 820651 is about 905.8978971164. The cubic root of 820651 is about 93.6237791752.

Adding to 820651 its reverse (156028), we get a palindrome (976679).

The spelling of 820651 in words is "eight hundred twenty thousand, six hundred fifty-one".