821255004 has 24 divisors (see below), whose sum is σ = 2129179920. Its totient is φ = 273751632.

The previous prime is 821255003. The next prime is 821255011. The reversal of 821255004 is 400552128.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821255003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3801999 + ... + 3802214.

It is an arithmetic number, because the mean of its divisors is an integer number (88715830).

Almost surely, 2^821255004 is an apocalyptic number.

It is an amenable number.

821255004 is an abundant number, since it is smaller than the sum of its proper divisors (1307924916).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821255004 is a wasteful number, since it uses less digits than its factorization.

821255004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7604226 (or 7604218 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 821255004 is about 28657.5470687915. The cubic root of 821255004 is about 936.4674276114.

The spelling of 821255004 in words is "eight hundred twenty-one million, two hundred fifty-five thousand, four".