820429217969 has 4 divisors (see below), whose sum is σ = 821641078644. Its totient is φ = 819217357296.

The previous prime is 820429217921. The next prime is 820429217977. The reversal of 820429217969 is 969712924028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 391797127969 + 428632090000 = 625937^2 + 654700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820429217969 is a prime.

It is a super-2 number, since 2×820429217969² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820429217999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605929322 + ... + 605930675.

It is an arithmetic number, because the mean of its divisors is an integer number (205410269661).

Almost surely, 2^820429217969 is an apocalyptic number.

It is an amenable number.

820429217969 is a deficient number, since it is larger than the sum of its proper divisors (1211860675).

820429217969 is a wasteful number, since it uses less digits than its factorization.

820429217969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1211860674.

The product of its (nonzero) digits is 7838208, while the sum is 59.

The spelling of 820429217969 in words is "eight hundred twenty billion, four hundred twenty-nine million, two hundred seventeen thousand, nine hundred sixty-nine".