21120099997 has 2 divisors, whose sum is σ = 21120099998. Its totient is φ = 21120099996.

The previous prime is 21120099989. The next prime is 21120100039. The reversal of 21120099997 is 79999002112.

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., 15758785156 + 5361314841 = 125534^2 + 73221^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120099997 - 2³ = 21120099989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21120099997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120099977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560049998 + 10560049999.

It is an arithmetic number, because the mean of its divisors is an integer number (10560049999).

Almost surely, 2^21120099997 is an apocalyptic number.

It is an amenable number.

21120099997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120099997 is an equidigital number, since it uses as much as digits as its factorization.

21120099997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 183708, while the sum is 49.

The spelling of 21120099997 in words is "twenty-one billion, one hundred twenty million, ninety-nine thousand, nine hundred ninety-seven".