19991963 has 2 divisors, whose sum is σ = 19991964. Its totient is φ = 19991962.

The previous prime is 19991911. The next prime is 19991989. The reversal of 19991963 is 36919991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19991963 - 2²² = 15797659 is a prime.

It is not a weakly prime, because it can be changed into another prime (19991563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9995981 + 9995982.

It is an arithmetic number, because the mean of its divisors is an integer number (9995982).

Almost surely, 2^19991963 is an apocalyptic number.

19991963 is a deficient number, since it is larger than the sum of its proper divisors (1).

19991963 is an equidigital number, since it uses as much as digits as its factorization.

19991963 is an evil number, because the sum of its binary digits is even.

The product of its digits is 118098, while the sum is 47.

The square root of 19991963 is about 4471.2373007927. The cubic root of 19991963 is about 271.4053971641.

The spelling of 19991963 in words is "nineteen million, nine hundred ninety-one thousand, nine hundred sixty-three".