664210978 has 8 divisors (see below), whose sum is σ = 1054923372. Its totient is φ = 312569856.

The previous prime is 664210957. The next prime is 664210979. The reversal of 664210978 is 879012466.

It can be written as a sum of positive squares in 2 ways, for example, as 635191209 + 29019769 = 25203^2 + 5387^2 .

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

It is not an unprimeable number, because it can be changed into a prime (664210979) 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, 9767775 + ... + 9767842.

Almost surely, 2^664210978 is an apocalyptic number.

664210978 is a deficient number, since it is larger than the sum of its proper divisors (390712394).

664210978 is a wasteful number, since it uses less digits than its factorization.

664210978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19535636.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 664210978 is about 25772.2908954559. The cubic root of 664210978 is about 872.5065241998.

The spelling of 664210978 in words is "six hundred sixty-four million, two hundred ten thousand, nine hundred seventy-eight".