1664061978 has 32 divisors (see below), whose sum is σ = 3421532160. Its totient is φ = 539276400.

The previous prime is 1664061941. The next prime is 1664062027. The reversal of 1664061978 is 8791604661.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23043 + ... + 62121.

It is an arithmetic number, because the mean of its divisors is an integer number (106922880).

Almost surely, 2^1664061978 is an apocalyptic number.

1664061978 is an abundant number, since it is smaller than the sum of its proper divisors (1757470182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1664061978 is a wasteful number, since it uses less digits than its factorization.

1664061978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39282.

The product of its (nonzero) digits is 435456, while the sum is 48.

The square root of 1664061978 is about 40792.9157820325. The cubic root of 1664061978 is about 1185.0131394865.

The spelling of 1664061978 in words is "one billion, six hundred sixty-four million, sixty-one thousand, nine hundred seventy-eight".