2191667551 has 4 divisors (see below), whose sum is σ = 2196660400. Its totient is φ = 2186674704.

The previous prime is 2191667507. The next prime is 2191667573. The reversal of 2191667551 is 1557661912.

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 2191667551 - 2⁹ = 2191667039 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2191667498 and 2191667507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191661551) 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, 2495766 + ... + 2496643.

It is an arithmetic number, because the mean of its divisors is an integer number (549165100).

Almost surely, 2^2191667551 is an apocalyptic number.

2191667551 is a deficient number, since it is larger than the sum of its proper divisors (4992849).

2191667551 is an equidigital number, since it uses as much as digits as its factorization.

2191667551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4992848.

The product of its digits is 113400, while the sum is 43.

The square root of 2191667551 is about 46815.2491288896. The cubic root of 2191667551 is about 1298.9473828314.

The spelling of 2191667551 in words is "two billion, one hundred ninety-one million, six hundred sixty-seven thousand, five hundred fifty-one".