13779804721 has 2 divisors, whose sum is σ = 13779804722. Its totient is φ = 13779804720.

The previous prime is 13779804697. The next prime is 13779804757. The reversal of 13779804721 is 12740897731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11256149025 + 2523655696 = 106095^2 + 50236^2 .

It is a cyclic number.

It is not a de Polignac number, because 13779804721 - 2⁷ = 13779804593 is a prime.

It is not a weakly prime, because it can be changed into another prime (13779804821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6889902360 + 6889902361.

It is an arithmetic number, because the mean of its divisors is an integer number (6889902361).

Almost surely, 2^13779804721 is an apocalyptic number.

It is an amenable number.

13779804721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13779804721 is an equidigital number, since it uses as much as digits as its factorization.

13779804721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 592704, while the sum is 49.

The spelling of 13779804721 in words is "thirteen billion, seven hundred seventy-nine million, eight hundred four thousand, seven hundred twenty-one".