820066821 has 8 divisors (see below), whose sum is σ = 1249625664. Its totient is φ = 468609600.

The previous prime is 820066811. The next prime is 820066837. The reversal of 820066821 is 128660028.

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

It is not a de Polignac number, because 820066821 - 2¹⁸ = 819804677 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820066811) 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, 19525380 + ... + 19525421.

It is an arithmetic number, because the mean of its divisors is an integer number (156203208).

Almost surely, 2^820066821 is an apocalyptic number.

It is an amenable number.

820066821 is a deficient number, since it is larger than the sum of its proper divisors (429558843).

820066821 is a wasteful number, since it uses less digits than its factorization.

820066821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39050811.

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 820066821 is about 28636.8088480543. The cubic root of 820066821 is about 936.0155859319.

The spelling of 820066821 in words is "eight hundred twenty million, sixty-six thousand, eight hundred twenty-one".