68121520 has 20 divisors (see below), whose sum is σ = 158382720. Its totient is φ = 27248576.

The previous prime is 68121497. The next prime is 68121523. The reversal of 68121520 is 2512186.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×68121520² = 9281082974220800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (68121523) 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 3 ways as a sum of consecutive naturals, for example, 425680 + ... + 425839.

It is an arithmetic number, because the mean of its divisors is an integer number (7919136).

Almost surely, 2^68121520 is an apocalyptic number.

It is an amenable number.

68121520 is an abundant number, since it is smaller than the sum of its proper divisors (90261200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

68121520 is a wasteful number, since it uses less digits than its factorization.

68121520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851532 (or 851526 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 68121520 is about 8253.5761945959. The cubic root of 68121520 is about 408.4085040932.

It can be divided in two parts, 681 and 21520, that added together give a square (22201 = 149²).

The spelling of 68121520 in words is "sixty-eight million, one hundred twenty-one thousand, five hundred twenty".