68915221 has 2 divisors, whose sum is σ = 68915222. Its totient is φ = 68915220.

The previous prime is 68915213. The next prime is 68915237. The reversal of 68915221 is 12251986.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66994225 + 1920996 = 8185^2 + 1386^2 .

It is a cyclic number.

It is not a de Polignac number, because 68915221 - 2³ = 68915213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68910221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34457610 + 34457611.

It is an arithmetic number, because the mean of its divisors is an integer number (34457611).

Almost surely, 2^68915221 is an apocalyptic number.

It is an amenable number.

68915221 is a deficient number, since it is larger than the sum of its proper divisors (1).

68915221 is an equidigital number, since it uses as much as digits as its factorization.

68915221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 68915221 is about 8301.5191983155. The cubic root of 68915221 is about 409.9885402310.

The spelling of 68915221 in words is "sixty-eight million, nine hundred fifteen thousand, two hundred twenty-one".