68417721 has 12 divisors (see below), whose sum is σ = 98901348. Its totient is φ = 45576864.

The previous prime is 68417719. The next prime is 68417737. The reversal of 68417721 is 12771486.

It can be written as a sum of positive squares in 2 ways, for example, as 47073321 + 21344400 = 6861^2 + 4620^2 .

It is not a de Polignac number, because 68417721 - 2¹ = 68417719 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68417021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15831 + ... + 19683.

It is an arithmetic number, because the mean of its divisors is an integer number (8241779).

Almost surely, 2^68417721 is an apocalyptic number.

It is an amenable number.

68417721 is a deficient number, since it is larger than the sum of its proper divisors (30483627).

68417721 is a wasteful number, since it uses less digits than its factorization.

68417721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5832 (or 5829 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 68417721 is about 8271.5005289246. The cubic root of 68417721 is about 408.9995855273. Note that the first 3 decimals are identical.

The spelling of 68417721 in words is "sixty-eight million, four hundred seventeen thousand, seven hundred twenty-one".