1664532540 has 144 divisors (see below), whose sum is σ = 5747728896. Its totient is φ = 385968000.

The previous prime is 1664532533. The next prime is 1664532599. The reversal of 1664532540 is 452354661.

1664532540 is a `hidden beast` number, since 1 + 6 + 64 + 53 + 2 + 540 = 666.

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 = 1664532495 and 1664532504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 27265 + ... + 63815.

It is an arithmetic number, because the mean of its divisors is an integer number (39914784).

Almost surely, 2^1664532540 is an apocalyptic number.

1664532540 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 1664532540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2873864448).

1664532540 is an abundant number, since it is smaller than the sum of its proper divisors (4083196356).

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

1664532540 is a wasteful number, since it uses less digits than its factorization.

1664532540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36600 (or 36595 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 1664532540 is about 40798.6830669815. The cubic root of 1664532540 is about 1185.1248279547.

The spelling of 1664532540 in words is "one billion, six hundred sixty-four million, five hundred thirty-two thousand, five hundred forty".