1881948209 has 2 divisors, whose sum is σ = 1881948210. Its totient is φ = 1881948208.

The previous prime is 1881948203. The next prime is 1881948239. The reversal of 1881948209 is 9028491881.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1666680625 + 215267584 = 40825^2 + 14672^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1881948209 is a prime.

It is a super-2 number, since 2×1881948209² = 7083458122716615362, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1881948203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 940974104 + 940974105.

It is an arithmetic number, because the mean of its divisors is an integer number (940974105).

Almost surely, 2^1881948209 is an apocalyptic number.

It is an amenable number.

1881948209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1881948209 is an equidigital number, since it uses as much as digits as its factorization.

1881948209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 331776, while the sum is 50.

The square root of 1881948209 is about 43381.4270051136. The cubic root of 1881948209 is about 1234.6273379365.

The spelling of 1881948209 in words is "one billion, eight hundred eighty-one million, nine hundred forty-eight thousand, two hundred nine".