664673659650 has 672 divisors, whose sum is σ = 2488874951808. Its totient is φ = 127482854400.

The previous prime is 664673659621. The next prime is 664673659693. The reversal of 664673659650 is 56956376466.

664673659650 is a `hidden beast` number, since 6 + 6 + 4 + 6 + 7 + 36 + 596 + 5 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 335 ways as a sum of consecutive naturals, for example, 36477342 + ... + 36495558.

It is an arithmetic number, because the mean of its divisors is an integer number (3703682964).

Almost surely, 2^664673659650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664673659650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1244437475904).

664673659650 is an abundant number, since it is smaller than the sum of its proper divisors (1824201292158).

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

664673659650 is a wasteful number, since it uses less digits than its factorization.

664673659650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18278 (or 18258 counting only the distinct ones).

The product of its (nonzero) digits is 146966400, while the sum is 63.

The spelling of 664673659650 in words is "six hundred sixty-four billion, six hundred seventy-three million, six hundred fifty-nine thousand, six hundred fifty".