820221758402 has 54 divisors (see below), whose sum is σ = 1288410114411. Its totient is φ = 391616796480.

The previous prime is 820221758333. The next prime is 820221758423. The reversal of 820221758402 is 204857122028.

It can be written as a sum of positive squares in 5 ways, for example, as 709080200761 + 111141557641 = 842069^2 + 333379^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=640399.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 820221758402.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2918938502 + ... + 2918938782.

Almost surely, 2^820221758402 is an apocalyptic number.

820221758402 is a deficient number, since it is larger than the sum of its proper divisors (468188356009).

820221758402 is an frugal number, since it uses more digits than its factorization.

820221758402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756 (or 379 counting only the distinct ones).

The product of its (nonzero) digits is 143360, while the sum is 41.

The spelling of 820221758402 in words is "eight hundred twenty billion, two hundred twenty-one million, seven hundred fifty-eight thousand, four hundred two".