1664020400 has 180 divisors, whose sum is σ = 4718271672. Its totient is φ = 562222080.

The previous prime is 1664020373. The next prime is 1664020417. The reversal of 1664020400 is 40204661.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1430219 + ... + 1431381.

Almost surely, 2^1664020400 is an apocalyptic number.

1664020400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1664020400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359135836).

1664020400 is an abundant number, since it is smaller than the sum of its proper divisors (3054251272).

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

1664020400 is a wasteful number, since it uses less digits than its factorization.

1664020400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1268 (or 1250 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 1664020400 is about 40792.4061560482. The cubic root of 1664020400 is about 1185.0032698848.

The spelling of 1664020400 in words is "one billion, six hundred sixty-four million, twenty thousand, four hundred".