378166661 has 4 divisors (see below), whose sum is σ = 383493024. Its totient is φ = 372840300.

The previous prime is 378166643. The next prime is 378166669. The reversal of 378166661 is 166661873.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-378166661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (378166669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2663075 + ... + 2663216.

It is an arithmetic number, because the mean of its divisors is an integer number (95873256).

Almost surely, 2^378166661 is an apocalyptic number.

It is an amenable number.

378166661 is a deficient number, since it is larger than the sum of its proper divisors (5326363).

378166661 is an equidigital number, since it uses as much as digits as its factorization.

378166661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5326362.

The product of its digits is 217728, while the sum is 44.

The square root of 378166661 is about 19446.5076813293. The cubic root of 378166661 is about 723.1489273216.

The spelling of 378166661 in words is "three hundred seventy-eight million, one hundred sixty-six thousand, six hundred sixty-one".