2078638421 has 4 divisors (see below), whose sum is σ = 2082722700. Its totient is φ = 2074554144.

The previous prime is 2078638417. The next prime is 2078638477. The reversal of 2078638421 is 1248368702.

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 1663497796 + 415140625 = 40786^2 + 20375^2 .

It is a cyclic number.

It is not a de Polignac number, because 2078638421 - 2² = 2078638417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2078638411) 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 3 ways as a sum of consecutive naturals, for example, 2041376 + ... + 2042393.

It is an arithmetic number, because the mean of its divisors is an integer number (520680675).

Almost surely, 2^2078638421 is an apocalyptic number.

It is an amenable number.

2078638421 is a deficient number, since it is larger than the sum of its proper divisors (4084279).

2078638421 is an equidigital number, since it uses as much as digits as its factorization.

2078638421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4084278.

The product of its (nonzero) digits is 129024, while the sum is 41.

The square root of 2078638421 is about 45592.0872630328. The cubic root of 2078638421 is about 1276.2222642353. Note that the first 4 decimals are identical.

The spelling of 2078638421 in words is "two billion, seventy-eight million, six hundred thirty-eight thousand, four hundred twenty-one".