842428429921 has 15 divisors (see below), whose sum is σ = 912796412613. Its totient is φ = 777483060120.

The previous prime is 842428429903. The next prime is 842428429939. The reversal of 842428429921 is 129924824248.

The square root of 842428429921 is 917839.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (842428429903) and next prime (842428429939).

It can be written as a sum of positive squares in 2 ways, for example, as 417689471521 + 424738958400 = 646289^2 + 651720^2 .

It is not a de Polignac number, because 842428429921 - 2¹³ = 842428421729 is a prime.

It is a super-2 number, since 2×842428429921² (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 (842428424921) 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 14 ways as a sum of consecutive naturals, for example, 155112076 + ... + 155117506.

Almost surely, 2^842428429921 is an apocalyptic number.

842428429921 is the 917839-th square number.

842428429921 is the 458920-th centered octagonal number.

It is an amenable number.

842428429921 is a deficient number, since it is larger than the sum of its proper divisors (70367982692).

842428429921 is an frugal number, since it uses more digits than its factorization.

842428429921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10914 (or 5444 counting only the distinct ones).

The product of its digits is 5308416, while the sum is 55.

The spelling of 842428429921 in words is "eight hundred forty-two billion, four hundred twenty-eight million, four hundred twenty-nine thousand, nine hundred twenty-one".