1664010427 has 4 divisors (see below), whose sum is σ = 1664094240. Its totient is φ = 1663926616.

The previous prime is 1664010391. The next prime is 1664010433. The reversal of 1664010427 is 7240104661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7240104661 = 43 ⋅168374527.

It is a cyclic number.

It is not a de Polignac number, because 1664010427 - 2¹⁵ = 1663977659 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1664010497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6558 + ... + 58060.

It is an arithmetic number, because the mean of its divisors is an integer number (416023560).

Almost surely, 2^1664010427 is an apocalyptic number.

1664010427 is a deficient number, since it is larger than the sum of its proper divisors (83813).

1664010427 is an equidigital number, since it uses as much as digits as its factorization.

1664010427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83812.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 1664010427 is about 40792.2839149759. The cubic root of 1664010427 is about 1185.0009025137. Note that the first 3 decimals are identical.

The spelling of 1664010427 in words is "one billion, six hundred sixty-four million, ten thousand, four hundred twenty-seven".