1999920361 has 2 divisors, whose sum is σ = 1999920362. Its totient is φ = 1999920360.

The previous prime is 1999920347. The next prime is 1999920389. The reversal of 1999920361 is 1630299991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1975269136 + 24651225 = 44444^2 + 4965^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999920361 - 2⁹ = 1999919849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1999920331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999960180 + 999960181.

It is an arithmetic number, because the mean of its divisors is an integer number (999960181).

Almost surely, 2^1999920361 is an apocalyptic number.

It is an amenable number.

1999920361 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999920361 is an equidigital number, since it uses as much as digits as its factorization.

1999920361 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 236196, while the sum is 49.

The square root of 1999920361 is about 44720.4691500436. The cubic root of 1999920361 is about 1259.9043265308.

The spelling of 1999920361 in words is "one billion, nine hundred ninety-nine million, nine hundred twenty thousand, three hundred sixty-one".