1881781331 has 2 divisors, whose sum is σ = 1881781332. Its totient is φ = 1881781330.

The previous prime is 1881781327. The next prime is 1881781339. The reversal of 1881781331 is 1331871881.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1331871881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1881781331 - 2² = 1881781327 is a prime.

It is a super-2 number, since 2×1881781331² = 7082201955400263122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1881781339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 940890665 + 940890666.

It is an arithmetic number, because the mean of its divisors is an integer number (940890666).

Almost surely, 2^1881781331 is an apocalyptic number.

1881781331 is a deficient number, since it is larger than the sum of its proper divisors (1).

1881781331 is an equidigital number, since it uses as much as digits as its factorization.

1881781331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32256, while the sum is 41.

The square root of 1881781331 is about 43379.5035817608. The cubic root of 1881781331 is about 1234.5908441530.

The spelling of 1881781331 in words is "one billion, eight hundred eighty-one million, seven hundred eighty-one thousand, three hundred thirty-one".