6655315921 has 2 divisors, whose sum is σ = 6655315922. Its totient is φ = 6655315920.

The previous prime is 6655315829. The next prime is 6655315943. The reversal of 6655315921 is 1295135566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3373286400 + 3282029521 = 58080^2 + 57289^2 .

It is a cyclic number.

It is not a de Polignac number, because 6655315921 - 2¹⁵ = 6655283153 is a prime.

It is not a weakly prime, because it can be changed into another prime (6655315981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3327657960 + 3327657961.

It is an arithmetic number, because the mean of its divisors is an integer number (3327657961).

Almost surely, 2^6655315921 is an apocalyptic number.

It is an amenable number.

6655315921 is a deficient number, since it is larger than the sum of its proper divisors (1).

6655315921 is an equidigital number, since it uses as much as digits as its factorization.

6655315921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 243000, while the sum is 43.

The square root of 6655315921 is about 81580.1196432072. The cubic root of 6655315921 is about 1881.0033049126.

The spelling of 6655315921 in words is "six billion, six hundred fifty-five million, three hundred fifteen thousand, nine hundred twenty-one".