1664234640 has 160 divisors (see below), whose sum is σ = 5771952000. Its totient is φ = 440732160.

The previous prime is 1664234623. The next prime is 1664234657. The reversal of 1664234640 is 464324661.

1664234640 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 2 + 3 + 4 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (1664234623) and next prime (1664234657).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1664234595 and 1664234604.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 319255 + ... + 324425.

It is an arithmetic number, because the mean of its divisors is an integer number (36074700).

Almost surely, 2^1664234640 is an apocalyptic number.

1664234640 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 1664234640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2885976000).

1664234640 is an abundant number, since it is smaller than the sum of its proper divisors (4107717360).

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

1664234640 is a wasteful number, since it uses less digits than its factorization.

1664234640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5342 (or 5330 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 1664234640 is about 40795.0320504838. The cubic root of 1664234640 is about 1185.0541234693.

The spelling of 1664234640 in words is "one billion, six hundred sixty-four million, two hundred thirty-four thousand, six hundred forty".