68721905 has 16 divisors (see below), whose sum is σ = 99792000. Its totient is φ = 44351232.

The previous prime is 68721847. The next prime is 68721923. The reversal of 68721905 is 50912786.

It is not a de Polignac number, because 68721905 - 2⁸ = 68721649 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57155 + ... + 58344.

It is an arithmetic number, because the mean of its divisors is an integer number (6237000).

Almost surely, 2^68721905 is an apocalyptic number.

It is an amenable number.

68721905 is a deficient number, since it is larger than the sum of its proper divisors (31070095).

68721905 is a wasteful number, since it uses less digits than its factorization.

68721905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115528.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 68721905 is about 8289.8676105231. The cubic root of 68721905 is about 409.6048244703.

The spelling of 68721905 in words is "sixty-eight million, seven hundred twenty-one thousand, nine hundred five".