68755021 has 4 divisors (see below), whose sum is σ = 72799452. Its totient is φ = 64710592.

The previous prime is 68755013. The next prime is 68755039. The reversal of 68755021 is 12055786.

68755021 = 1136² + 1137² + ... + 1186².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12055786 = 2 ⋅6027893.

It can be written as a sum of positive squares in 2 ways, for example, as 46049796 + 22705225 = 6786^2 + 4765^2 .

It is a cyclic number.

It is not a de Polignac number, because 68755021 - 2³ = 68755013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68750021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2022190 + ... + 2022223.

It is an arithmetic number, because the mean of its divisors is an integer number (18199863).

Almost surely, 2^68755021 is an apocalyptic number.

It is an amenable number.

68755021 is a deficient number, since it is larger than the sum of its proper divisors (4044431).

68755021 is a wasteful number, since it uses less digits than its factorization.

68755021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4044430.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 68755021 is about 8291.8647480528. The cubic root of 68755021 is about 409.6706079354.

The spelling of 68755021 in words is "sixty-eight million, seven hundred fifty-five thousand, twenty-one".