1664827561 has 36 divisors (see below), whose sum is σ = 1910846592. Its totient is φ = 1446787584.

The previous prime is 1664827553. The next prime is 1664827631. The reversal of 1664827561 is 1657284661.

It is not a de Polignac number, because 1664827561 - 2³ = 1664827553 is a prime.

It is a Duffinian number.

Its product of digits (483840) is a multiple of the sum of its prime divisors (160).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664827061) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 22805821 + ... + 22805893.

It is an arithmetic number, because the mean of its divisors is an integer number (53079072).

Almost surely, 2^1664827561 is an apocalyptic number.

It is an amenable number.

1664827561 is a deficient number, since it is larger than the sum of its proper divisors (246019031).

1664827561 is an equidigital number, since it uses as much as digits as its factorization.

1664827561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 160 counting only the distinct ones).

The product of its digits is 483840, while the sum is 46.

The square root of 1664827561 is about 40802.2984769241. The cubic root of 1664827561 is about 1185.1948408160.

The spelling of 1664827561 in words is "one billion, six hundred sixty-four million, eight hundred twenty-seven thousand, five hundred sixty-one".