20011209997 has 2 divisors, whose sum is σ = 20011209998. Its totient is φ = 20011209996.

The previous prime is 20011209973. The next prime is 20011210057. The reversal of 20011209997 is 79990211002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18618875401 + 1392334596 = 136451^2 + 37314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20011209997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20011209797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005604998 + 10005604999.

It is an arithmetic number, because the mean of its divisors is an integer number (10005604999).

Almost surely, 2^20011209997 is an apocalyptic number.

It is an amenable number.

20011209997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20011209997 is an equidigital number, since it uses as much as digits as its factorization.

20011209997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20412, while the sum is 40.

The spelling of 20011209997 in words is "twenty billion, eleven million, two hundred nine thousand, nine hundred ninety-seven".