997777666 has 8 divisors (see below), whose sum is σ = 1575438480. Its totient is φ = 472631508.

The previous prime is 997777657. The next prime is 997777667. The reversal of 997777666 is 666777799.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 997777598 and 997777607.

It is not an unprimeable number, because it can be changed into a prime (997777667) 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, 13128616 + ... + 13128691.

It is an arithmetic number, because the mean of its divisors is an integer number (196929810).

Almost surely, 2^997777666 is an apocalyptic number.

997777666 is a deficient number, since it is larger than the sum of its proper divisors (577660814).

997777666 is a wasteful number, since it uses less digits than its factorization.

997777666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26257328.

The product of its digits is 42007896, while the sum is 64.

The square root of 997777666 is about 31587.6188719568. The cubic root of 997777666 is about 999.2586725694.

The spelling of 997777666 in words is "nine hundred ninety-seven million, seven hundred seventy-seven thousand, six hundred sixty-six".