66881719 has 2 divisors, whose sum is σ = 66881720. Its totient is φ = 66881718.

The previous prime is 66881699. The next prime is 66881747. The reversal of 66881719 is 91718866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66881719 - 2²³ = 58493111 is a prime.

It is a super-2 number, since 2×66881719² = 8946328672789922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66882719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33440859 + 33440860.

It is an arithmetic number, because the mean of its divisors is an integer number (33440860).

Almost surely, 2^66881719 is an apocalyptic number.

66881719 is a deficient number, since it is larger than the sum of its proper divisors (1).

66881719 is an equidigital number, since it uses as much as digits as its factorization.

66881719 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 46.

The square root of 66881719 is about 8178.1244182270. The cubic root of 66881719 is about 405.9156623091.

It can be divided in two parts, 66881 and 719, that added together give a square (67600 = 260²).

The spelling of 66881719 in words is "sixty-six million, eight hundred eighty-one thousand, seven hundred nineteen".