67639993 has 2 divisors, whose sum is σ = 67639994. Its totient is φ = 67639992.

The previous prime is 67639969. The next prime is 67640009. The reversal of 67639993 is 39993676.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67453369 + 186624 = 8213^2 + 432^2 .

It is a cyclic number.

It is not a de Polignac number, because 67639993 - 2⁵ = 67639961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 67639993.

It is not a weakly prime, because it can be changed into another prime (67639933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33819996 + 33819997.

It is an arithmetic number, because the mean of its divisors is an integer number (33819997).

Almost surely, 2^67639993 is an apocalyptic number.

It is an amenable number.

67639993 is a deficient number, since it is larger than the sum of its proper divisors (1).

67639993 is an equidigital number, since it uses as much as digits as its factorization.

67639993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1653372, while the sum is 52.

The square root of 67639993 is about 8224.3536524155. The cubic root of 67639993 is about 407.4439292041.

The spelling of 67639993 in words is "sixty-seven million, six hundred thirty-nine thousand, nine hundred ninety-three".