19912129997 has 2 divisors, whose sum is σ = 19912129998. Its totient is φ = 19912129996.

The previous prime is 19912129967. The next prime is 19912130003. The reversal of 19912129997 is 79992121991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12716170756 + 7195959241 = 112766^2 + 84829^2 .

It is a cyclic number.

It is not a de Polignac number, because 19912129997 - 2¹² = 19912125901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19912129967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9956064998 + 9956064999.

It is an arithmetic number, because the mean of its divisors is an integer number (9956064999).

Almost surely, 2^19912129997 is an apocalyptic number.

It is an amenable number.

19912129997 is a deficient number, since it is larger than the sum of its proper divisors (1).

19912129997 is an equidigital number, since it uses as much as digits as its factorization.

19912129997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1653372, while the sum is 59.

The spelling of 19912129997 in words is "nineteen billion, nine hundred twelve million, one hundred twenty-nine thousand, nine hundred ninety-seven".