1664400125 has 36 divisors (see below), whose sum is σ = 2153260668. Its totient is φ = 1284448000.

The previous prime is 1664400091. The next prime is 1664400149. The reversal of 1664400125 is 5210044661.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 18 ways, for example, as 947285284 + 717114841 = 30778^2 + 26779^2 .

It is not a de Polignac number, because 1664400125 - 2¹⁶ = 1664334589 is a prime.

It is a super-2 number, since 2×1664400125² = 5540455552200031250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 18701081 + ... + 18701169.

Almost surely, 2^1664400125 is an apocalyptic number.

It is an amenable number.

1664400125 is a deficient number, since it is larger than the sum of its proper divisors (488860543).

1664400125 is an frugal number, since it uses more digits than its factorization.

1664400125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 275 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 1664400125 is about 40797.0602494837. The cubic root of 1664400125 is about 1185.0934012204.

Adding to 1664400125 its reverse (5210044661), we get a palindrome (6874444786).

The spelling of 1664400125 in words is "one billion, six hundred sixty-four million, four hundred thousand, one hundred twenty-five".