1969946821 has 2 divisors, whose sum is σ = 1969946822. Its totient is φ = 1969946820.

The previous prime is 1969946819. The next prime is 1969946843. The reversal of 1969946821 is 1286499691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1811438721 + 158508100 = 42561^2 + 12590^2 .

It is a cyclic number.

It is not a de Polignac number, because 1969946821 - 2¹ = 1969946819 is a prime.

Together with 1969946819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1969946921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 984973410 + 984973411.

It is an arithmetic number, because the mean of its divisors is an integer number (984973411).

Almost surely, 2^1969946821 is an apocalyptic number.

It is an amenable number.

1969946821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1969946821 is an equidigital number, since it uses as much as digits as its factorization.

1969946821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1679616, while the sum is 55.

The square root of 1969946821 is about 44384.0829690104. The cubic root of 1969946821 is about 1253.5784014062.

The spelling of 1969946821 in words is "one billion, nine hundred sixty-nine million, nine hundred forty-six thousand, eight hundred twenty-one".