997621666 has 8 divisors (see below), whose sum is σ = 1506343104. Its totient is φ = 495507300.

The previous prime is 997621631. The next prime is 997621679. The reversal of 997621666 is 666126799.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1651390 + ... + 1651993.

It is an arithmetic number, because the mean of its divisors is an integer number (188292888).

Almost surely, 2^997621666 is an apocalyptic number.

997621666 is a deficient number, since it is larger than the sum of its proper divisors (508721438).

997621666 is a wasteful number, since it uses less digits than its factorization.

997621666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3303536.

The product of its digits is 1469664, while the sum is 52.

The square root of 997621666 is about 31585.1494535011. The cubic root of 997621666 is about 999.2065926713.

The spelling of 997621666 in words is "nine hundred ninety-seven million, six hundred twenty-one thousand, six hundred sixty-six".