1988690881 has 2 divisors, whose sum is σ = 1988690882. Its totient is φ = 1988690880.

The previous prime is 1988690861. The next prime is 1988690927. The reversal of 1988690881 is 1880968891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1811268481 + 177422400 = 42559^2 + 13320^2 .

It is an emirp because it is prime and its reverse (1880968891) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1880698861 and 1688960881.

It is a cyclic number.

It is not a de Polignac number, because 1988690881 - 2¹⁷ = 1988559809 is a prime.

It is a super-2 number, since 2×1988690881² = 7909782840345112322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1988690831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994345440 + 994345441.

It is an arithmetic number, because the mean of its divisors is an integer number (994345441).

Almost surely, 2^1988690881 is an apocalyptic number.

It is an amenable number.

1988690881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988690881 is an equidigital number, since it uses as much as digits as its factorization.

1988690881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1990656, while the sum is 58.

The square root of 1988690881 is about 44594.7405082707. The cubic root of 1988690881 is about 1257.5417935142.

The spelling of 1988690881 in words is "one billion, nine hundred eighty-eight million, six hundred ninety thousand, eight hundred eighty-one".