1821687941 has 2 divisors, whose sum is σ = 1821687942. Its totient is φ = 1821687940.

The previous prime is 1821687919. The next prime is 1821687943. The reversal of 1821687941 is 1497861281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1804465441 + 17222500 = 42479^2 + 4150^2 .

It is a cyclic number.

It is not a de Polignac number, because 1821687941 - 2⁶ = 1821687877 is a prime.

Together with 1821687943, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1821687943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910843970 + 910843971.

It is an arithmetic number, because the mean of its divisors is an integer number (910843971).

Almost surely, 2^1821687941 is an apocalyptic number.

It is an amenable number.

1821687941 is a deficient number, since it is larger than the sum of its proper divisors (1).

1821687941 is an equidigital number, since it uses as much as digits as its factorization.

1821687941 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 47.

The square root of 1821687941 is about 42681.2364043030. The cubic root of 1821687941 is about 1221.3064793422.

The spelling of 1821687941 in words is "one billion, eight hundred twenty-one million, six hundred eighty-seven thousand, nine hundred forty-one".