66977731 has 2 divisors, whose sum is σ = 66977732. Its totient is φ = 66977730.

The previous prime is 66977693. The next prime is 66977753. The reversal of 66977731 is 13777966.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66977731 - 2¹¹ = 66975683 is a prime.

It is a super-2 number, since 2×66977731² = 8972032899816722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66975731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33488865 + 33488866.

It is an arithmetic number, because the mean of its divisors is an integer number (33488866).

Almost surely, 2^66977731 is an apocalyptic number.

66977731 is a deficient number, since it is larger than the sum of its proper divisors (1).

66977731 is an equidigital number, since it uses as much as digits as its factorization.

66977731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 333396, while the sum is 46.

The square root of 66977731 is about 8183.9923631440. The cubic root of 66977731 is about 406.1098067425.

It can be divided in two parts, 669 and 77731, that added together give a square (78400 = 280²).

The spelling of 66977731 in words is "sixty-six million, nine hundred seventy-seven thousand, seven hundred thirty-one".