67231981 has 2 divisors, whose sum is σ = 67231982. Its totient is φ = 67231980.

The previous prime is 67231897. The next prime is 67231987. The reversal of 67231981 is 18913276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39501225 + 27730756 = 6285^2 + 5266^2 .

It is a cyclic number.

It is not a de Polignac number, because 67231981 - 2¹¹ = 67229933 is a prime.

It is a super-2 number, since 2×67231981² = 9040278538368722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 67231981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67231987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33615990 + 33615991.

It is an arithmetic number, because the mean of its divisors is an integer number (33615991).

Almost surely, 2^67231981 is an apocalyptic number.

It is an amenable number.

67231981 is a deficient number, since it is larger than the sum of its proper divisors (1).

67231981 is an equidigital number, since it uses as much as digits as its factorization.

67231981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 37.

The square root of 67231981 is about 8199.5110220061. The cubic root of 67231981 is about 406.6230272829.

It can be divided in two parts, 672319 and 81, that added together give a square (672400 = 820²).

The spelling of 67231981 in words is "sixty-seven million, two hundred thirty-one thousand, nine hundred eighty-one".