684135064021 has 4 divisors (see below), whose sum is σ = 684362278944. Its totient is φ = 683907849100.

The previous prime is 684135064007. The next prime is 684135064049. The reversal of 684135064021 is 120460531486.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 684135064021 - 2⁷ = 684135063893 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 (684135064621) 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, 113602945 + ... + 113608966.

It is an arithmetic number, because the mean of its divisors is an integer number (171090569736).

Almost surely, 2^684135064021 is an apocalyptic number.

It is an amenable number.

684135064021 is a deficient number, since it is larger than the sum of its proper divisors (227214923).

684135064021 is a wasteful number, since it uses less digits than its factorization.

684135064021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227214922.

The product of its (nonzero) digits is 138240, while the sum is 40.

The spelling of 684135064021 in words is "six hundred eighty-four billion, one hundred thirty-five million, sixty-four thousand, twenty-one".