3918621046721 has 2 divisors, whose sum is σ = 3918621046722. Its totient is φ = 3918621046720.

The previous prime is 3918621046673. The next prime is 3918621046723. The reversal of 3918621046721 is 1276401268193.

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., 2433303609025 + 1485317437696 = 1559905^2 + 1218736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3918621046721 is a prime.

Together with 3918621046723, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3918621046721.

It is not a weakly prime, because it can be changed into another prime (3918621046723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1959310523360 + 1959310523361.

It is an arithmetic number, because the mean of its divisors is an integer number (1959310523361).

Almost surely, 2^{3918621046721} is an apocalyptic number.

It is an amenable number.

3918621046721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3918621046721 is an equidigital number, since it uses as much as digits as its factorization.

3918621046721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 50.

The spelling of 3918621046721 in words is "three trillion, nine hundred eighteen billion, six hundred twenty-one million, forty-six thousand, seven hundred twenty-one".