666100551 has 4 divisors (see below), whose sum is σ = 888134072. Its totient is φ = 444067032.

The previous prime is 666100549. The next prime is 666100571. The reversal of 666100551 is 155001666.

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

It is not a de Polignac number, because 666100551 - 2¹ = 666100549 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 (666100571) 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, 111016756 + ... + 111016761.

It is an arithmetic number, because the mean of its divisors is an integer number (222033518).

Almost surely, 2^666100551 is an apocalyptic number.

666100551 is a deficient number, since it is larger than the sum of its proper divisors (222033521).

666100551 is a wasteful number, since it uses less digits than its factorization.

666100551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222033520.

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 666100551 is about 25808.9238636562. The cubic root of 666100551 is about 873.3331209169. Note that the first 3 decimals are identical.

It can be divided in two parts, 666 and 100551, that multiplied together give a palindrome (66966966).

The spelling of 666100551 in words is "six hundred sixty-six million, one hundred thousand, five hundred fifty-one".