666472894 has 4 divisors (see below), whose sum is σ = 999709344. Its totient is φ = 333236446.

The previous prime is 666472889. The next prime is 666472901. The reversal of 666472894 is 498274666.

It is a happy number.

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

It is a super-2 number, since 2×666472894² = 888372236873470472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166618222 + ... + 166618225.

It is an arithmetic number, because the mean of its divisors is an integer number (249927336).

Almost surely, 2^666472894 is an apocalyptic number.

666472894 is a deficient number, since it is larger than the sum of its proper divisors (333236450).

666472894 is a wasteful number, since it uses less digits than its factorization.

666472894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333236449.

The product of its digits is 3483648, while the sum is 52.

The square root of 666472894 is about 25816.1363104551. The cubic root of 666472894 is about 873.4958185266.

The spelling of 666472894 in words is "six hundred sixty-six million, four hundred seventy-two thousand, eight hundred ninety-four".