66881668 has 18 divisors (see below), whose sum is σ = 136152366. Its totient is φ = 28663488.

The previous prime is 66881623. The next prime is 66881699. The reversal of 66881668 is 86618866.

It can be written as a sum of positive squares in only one way, i.e., 54434884 + 12446784 = 7378^2 + 3528^2 .

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 170421 + ... + 170812.

Almost surely, 2^66881668 is an apocalyptic number.

It is an amenable number.

66881668 is an abundant number, since it is smaller than the sum of its proper divisors (69270698).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66881668 is a wasteful number, since it uses less digits than its factorization.

66881668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341251 (or 341242 counting only the distinct ones).

The product of its digits is 663552, while the sum is 49.

The square root of 66881668 is about 8178.1213001520. The cubic root of 66881668 is about 405.9155591334.

The spelling of 66881668 in words is "sixty-six million, eight hundred eighty-one thousand, six hundred sixty-eight".