1666322251 has 4 divisors (see below), whose sum is σ = 1817806104. Its totient is φ = 1514838400.

The previous prime is 1666322243. The next prime is 1666322327. The reversal of 1666322251 is 1522236661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1666322251 - 2³ = 1666322243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666322051) 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, 75741910 + ... + 75741931.

It is an arithmetic number, because the mean of its divisors is an integer number (454451526).

Almost surely, 2^1666322251 is an apocalyptic number.

1666322251 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1666322251 is a deficient number, since it is larger than the sum of its proper divisors (151483853).

1666322251 is a wasteful number, since it uses less digits than its factorization.

1666322251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151483852.

The product of its digits is 25920, while the sum is 34.

The square root of 1666322251 is about 40820.6106152272. The cubic root of 1666322251 is about 1185.5494258851.

The spelling of 1666322251 in words is "one billion, six hundred sixty-six million, three hundred twenty-two thousand, two hundred fifty-one".