421516778929 has 4 divisors (see below), whose sum is σ = 423953292276. Its totient is φ = 419080265584.

The previous prime is 421516778867. The next prime is 421516778941. The reversal of 421516778929 is 929877615124.

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 248417512225 + 173099266704 = 498415^2 + 416052^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-421516778929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (421516778029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1218256414 + ... + 1218256759.

It is an arithmetic number, because the mean of its divisors is an integer number (105988323069).

Almost surely, 2^421516778929 is an apocalyptic number.

It is an amenable number.

421516778929 is a deficient number, since it is larger than the sum of its proper divisors (2436513347).

421516778929 is a wasteful number, since it uses less digits than its factorization.

421516778929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2436513346.

The product of its digits is 15240960, while the sum is 61.

The spelling of 421516778929 in words is "four hundred twenty-one billion, five hundred sixteen million, seven hundred seventy-eight thousand, nine hundred twenty-nine".