820251217020 has 48 divisors (see below), whose sum is σ = 2296814583168. Its totient is φ = 218723069760.

The previous prime is 820251216997. The next prime is 820251217033. The reversal of 820251217020 is 20712152028.

It is a super-2 number, since 2×820251217020² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 960615 + ... + 1601025.

It is an arithmetic number, because the mean of its divisors is an integer number (47850303816).

Almost surely, 2^820251217020 is an apocalyptic number.

It is an amenable number.

820251217020 is an abundant number, since it is smaller than the sum of its proper divisors (1476563366148).

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

820251217020 is a wasteful number, since it uses less digits than its factorization.

820251217020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661770 (or 661768 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 30.

Adding to 820251217020 its reverse (20712152028), we get a palindrome (840963369048).

The spelling of 820251217020 in words is "eight hundred twenty billion, two hundred fifty-one million, two hundred seventeen thousand, twenty".