6651559997 has 2 divisors, whose sum is σ = 6651559998. Its totient is φ = 6651559996.

The previous prime is 6651559949. The next prime is 6651560009. The reversal of 6651559997 is 7999551566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6644532196 + 7027801 = 81514^2 + 2651^2 .

It is a cyclic number.

It is not a de Polignac number, because 6651559997 - 2¹⁰ = 6651558973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6651559097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3325779998 + 3325779999.

It is an arithmetic number, because the mean of its divisors is an integer number (3325779999).

Almost surely, 2^6651559997 is an apocalyptic number.

It is an amenable number.

6651559997 is a deficient number, since it is larger than the sum of its proper divisors (1).

6651559997 is an equidigital number, since it uses as much as digits as its factorization.

6651559997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22963500, while the sum is 62.

The square root of 6651559997 is about 81557.0965459168. The cubic root of 6651559997 is about 1880.6493905889.

The spelling of 6651559997 in words is "six billion, six hundred fifty-one million, five hundred fifty-nine thousand, nine hundred ninety-seven".