1664489957 has 12 divisors (see below), whose sum is σ = 1807547364. Its totient is φ = 1532044800.

The previous prime is 1664489951. The next prime is 1664489971. The reversal of 1664489957 is 7599844661.

It can be written as a sum of positive squares in 6 ways, for example, as 66569281 + 1597920676 = 8159^2 + 39974^2 .

It is not a de Polignac number, because 1664489957 - 2¹⁰ = 1664488933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1664489896 and 1664489905.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664489951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45707 + ... + 73607.

It is an arithmetic number, because the mean of its divisors is an integer number (150628947).

Almost surely, 2^1664489957 is an apocalyptic number.

It is an amenable number.

1664489957 is a deficient number, since it is larger than the sum of its proper divisors (143057407).

1664489957 is a wasteful number, since it uses less digits than its factorization.

1664489957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28280 (or 28267 counting only the distinct ones).

The product of its digits is 13063680, while the sum is 59.

The square root of 1664489957 is about 40798.1611963088. The cubic root of 1664489957 is about 1185.1147216937.

It can be divided in two parts, 16644 and 89957, that added together give a palindrome (106601).

The spelling of 1664489957 in words is "one billion, six hundred sixty-four million, four hundred eighty-nine thousand, nine hundred fifty-seven".