68206921 has 4 divisors (see below), whose sum is σ = 68285572. Its totient is φ = 68128272.

The previous prime is 68206877. The next prime is 68206933. The reversal of 68206921 is 12960286.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31483321 + 36723600 = 5611^2 + 6060^2 .

It is a cyclic number.

It is not a de Polignac number, because 68206921 - 2¹⁵ = 68174153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68206961) 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, 38010 + ... + 39763.

It is an arithmetic number, because the mean of its divisors is an integer number (17071393).

Almost surely, 2^68206921 is an apocalyptic number.

It is an amenable number.

68206921 is a deficient number, since it is larger than the sum of its proper divisors (78651).

68206921 is an equidigital number, since it uses as much as digits as its factorization.

68206921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78650.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 68206921 is about 8258.7481496895. The cubic root of 68206921 is about 408.5791008424.

The spelling of 68206921 in words is "sixty-eight million, two hundred six thousand, nine hundred twenty-one".