1728611881 has 2 divisors, whose sum is σ = 1728611882. Its totient is φ = 1728611880.

The previous prime is 1728611873. The next prime is 1728611893. The reversal of 1728611881 is 1881168271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1528106281 + 200505600 = 39091^2 + 14160^2 .

It is a cyclic number.

It is not a de Polignac number, because 1728611881 - 2³ = 1728611873 is a prime.

It is a super-2 number, since 2×1728611881² = 5976198070268716322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1728611821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 864305940 + 864305941.

It is an arithmetic number, because the mean of its divisors is an integer number (864305941).

Almost surely, 2^1728611881 is an apocalyptic number.

It is an amenable number.

1728611881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1728611881 is an equidigital number, since it uses as much as digits as its factorization.

1728611881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43008, while the sum is 43.

The square root of 1728611881 is about 41576.5785148321. The cubic root of 1728611881 is about 1200.1416224056.

The spelling of 1728611881 in words is "one billion, seven hundred twenty-eight million, six hundred eleven thousand, eight hundred eighty-one".