661404166 has 4 divisors (see below), whose sum is σ = 992106252. Its totient is φ = 330702082.

The previous prime is 661404157. The next prime is 661404167.

661404166 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661404167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165351040 + ... + 165351043.

It is an arithmetic number, because the mean of its divisors is an integer number (248026563).

Almost surely, 2^661404166 is an apocalyptic number.

661404166 is a deficient number, since it is larger than the sum of its proper divisors (330702086).

661404166 is a wasteful number, since it uses less digits than its factorization.

661404166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330702085.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 661404166 is about 25717.7791809480. The cubic root of 661404166 is about 871.2757809675.

The spelling of 661404166 in words is "six hundred sixty-one million, four hundred four thousand, one hundred sixty-six".