68121639 has 6 divisors (see below), whose sum is σ = 98397936. Its totient is φ = 45414420.

The previous prime is 68121617. The next prime is 68121643. The reversal of 68121639 is 93612186.

68121639 is a `hidden beast` number, since 6 + 8 + 12 + 1 + 639 = 666.

It is not a de Polignac number, because 68121639 - 2⁹ = 68121127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68121649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3784527 + ... + 3784544.

It is an arithmetic number, because the mean of its divisors is an integer number (16399656).

Almost surely, 2^68121639 is an apocalyptic number.

68121639 is a deficient number, since it is larger than the sum of its proper divisors (30276297).

68121639 is a wasteful number, since it uses less digits than its factorization.

68121639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7569077 (or 7569074 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 68121639 is about 8253.5834035890. The cubic root of 68121639 is about 408.4087419064.

The spelling of 68121639 in words is "sixty-eight million, one hundred twenty-one thousand, six hundred thirty-nine".