16388219681 has 2 divisors, whose sum is σ = 16388219682. Its totient is φ = 16388219680.

The previous prime is 16388219677. The next prime is 16388219699. The reversal of 16388219681 is 18691288361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16387840225 + 379456 = 128015^2 + 616^2 .

It is a cyclic number.

It is not a de Polignac number, because 16388219681 - 2² = 16388219677 is a prime.

It is a super-2 number, since 2×16388219681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (16388219621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8194109840 + 8194109841.

It is an arithmetic number, because the mean of its divisors is an integer number (8194109841).

Almost surely, 2^16388219681 is an apocalyptic number.

It is an amenable number.

16388219681 is a deficient number, since it is larger than the sum of its proper divisors (1).

16388219681 is an equidigital number, since it uses as much as digits as its factorization.

16388219681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 995328, while the sum is 53.

The spelling of 16388219681 in words is "sixteen billion, three hundred eighty-eight million, two hundred nineteen thousand, six hundred eighty-one".