6621819493 has 2 divisors, whose sum is σ = 6621819494. Its totient is φ = 6621819492.

The previous prime is 6621819467. The next prime is 6621819499. The reversal of 6621819493 is 3949181266.

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., 6402720289 + 219099204 = 80017^2 + 14802^2 .

It is a cyclic number.

It is not a de Polignac number, because 6621819493 - 2⁵ = 6621819461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6621819499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3310909746 + 3310909747.

It is an arithmetic number, because the mean of its divisors is an integer number (3310909747).

Almost surely, 2^6621819493 is an apocalyptic number.

It is an amenable number.

6621819493 is a deficient number, since it is larger than the sum of its proper divisors (1).

6621819493 is an equidigital number, since it uses as much as digits as its factorization.

6621819493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The square root of 6621819493 is about 81374.5629358462. The cubic root of 6621819493 is about 1877.8422782312.

The spelling of 6621819493 in words is "six billion, six hundred twenty-one million, eight hundred nineteen thousand, four hundred ninety-three".