1664224661 has 4 divisors (see below), whose sum is σ = 1815517824. Its totient is φ = 1512931500.

The previous prime is 1664224651. The next prime is 1664224669.

1664224661 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1664224661 - 2¹⁴ = 1664208277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664224669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75646565 + ... + 75646586.

It is an arithmetic number, because the mean of its divisors is an integer number (453879456).

Almost surely, 2^1664224661 is an apocalyptic number.

1664224661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1664224661 is a deficient number, since it is larger than the sum of its proper divisors (151293163).

1664224661 is a wasteful number, since it uses less digits than its factorization.

1664224661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151293162.

The product of its digits is 82944, while the sum is 38.

The square root of 1664224661 is about 40794.9097437413. The cubic root of 1664224661 is about 1185.0517548773.

The spelling of 1664224661 in words is "one billion, six hundred sixty-four million, two hundred twenty-four thousand, six hundred sixty-one".