13908321781 has 2 divisors, whose sum is σ = 13908321782. Its totient is φ = 13908321780.

The previous prime is 13908321773. The next prime is 13908321797. The reversal of 13908321781 is 18712380931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13700702500 + 207619281 = 117050^2 + 14409^2 .

It is a cyclic number.

It is not a de Polignac number, because 13908321781 - 2³ = 13908321773 is a prime.

It is a super-2 number, since 2×13908321781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13908321751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6954160890 + 6954160891.

It is an arithmetic number, because the mean of its divisors is an integer number (6954160891).

Almost surely, 2^13908321781 is an apocalyptic number.

It is an amenable number.

13908321781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13908321781 is an equidigital number, since it uses as much as digits as its factorization.

13908321781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 43.

The spelling of 13908321781 in words is "thirteen billion, nine hundred eight million, three hundred twenty-one thousand, seven hundred eighty-one".