1666613957 has 4 divisors (see below), whose sum is σ = 1672764096. Its totient is φ = 1660463820.

The previous prime is 1666613953. The next prime is 1666613987. The reversal of 1666613957 is 7593166661.

It is a happy number.

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 1666613957 - 2² = 1666613953 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 (1666613951) 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, 3074663 + ... + 3075204.

It is an arithmetic number, because the mean of its divisors is an integer number (418191024).

Almost surely, 2^1666613957 is an apocalyptic number.

It is an amenable number.

1666613957 is a deficient number, since it is larger than the sum of its proper divisors (6150139).

1666613957 is an equidigital number, since it uses as much as digits as its factorization.

1666613957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6150138.

The product of its digits is 1224720, while the sum is 50.

The square root of 1666613957 is about 40824.1834823429. The cubic root of 1666613957 is about 1185.6186025209.

The spelling of 1666613957 in words is "one billion, six hundred sixty-six million, six hundred thirteen thousand, nine hundred fifty-seven".