772821 has 40 divisors (see below), whose sum is σ = 1393920. Its totient is φ = 417312.

The previous prime is 772789. The next prime is 772843. The reversal of 772821 is 128277.

It is not a de Polignac number, because 772821 - 2⁵ = 772789 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (772721) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 16420 + ... + 16466.

It is an arithmetic number, because the mean of its divisors is an integer number (34848).

2⁷⁷²⁸²¹ is an apocalyptic number.

It is an amenable number.

772821 is a deficient number, since it is larger than the sum of its proper divisors (621099).

772821 is a wasteful number, since it uses less digits than its factorization.

772821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 86 counting only the distinct ones).

The product of its digits is 1568, while the sum is 27.

The square root of 772821 is about 879.1023831159. The cubic root of 772821 is about 91.7683602356.

The spelling of 772821 in words is "seven hundred seventy-two thousand, eight hundred twenty-one".