1664542720 has 48 divisors (see below), whose sum is σ = 3993951780. Its totient is φ = 665812992.

The previous prime is 1664542687. The next prime is 1664542753. The reversal of 1664542720 is 272454661.

It is an interprime number because it is at equal distance from previous prime (1664542687) and next prime (1664542753).

It can be written as a sum of positive squares in 2 ways, for example, as 1526621184 + 137921536 = 39072^2 + 11744^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1664542720.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71037 + ... + 91516.

Almost surely, 2^1664542720 is an apocalyptic number.

1664542720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664542720 is an abundant number, since it is smaller than the sum of its proper divisors (2329409060).

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

1664542720 is an equidigital number, since it uses as much as digits as its factorization.

1664542720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162580 (or 162560 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 37.

The square root of 1664542720 is about 40798.8078257196. The cubic root of 1664542720 is about 1185.1272439575.

The spelling of 1664542720 in words is "one billion, six hundred sixty-four million, five hundred forty-two thousand, seven hundred twenty".