100021221997 has 2 divisors, whose sum is σ = 100021221998. Its totient is φ = 100021221996.

The previous prime is 100021221973. The next prime is 100021222031. The reversal of 100021221997 is 799122120001.

It is a happy number.

It is an a-pointer prime, because the next prime (100021222031) can be obtained adding 100021221997 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83621602276 + 16399619721 = 289174^2 + 128061^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100021221997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100021221907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50010610998 + 50010610999.

It is an arithmetic number, because the mean of its divisors is an integer number (50010610999).

Almost surely, 2^100021221997 is an apocalyptic number.

It is an amenable number.

100021221997 is a deficient number, since it is larger than the sum of its proper divisors (1).

100021221997 is an equidigital number, since it uses as much as digits as its factorization.

100021221997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 34.

Adding to 100021221997 its reverse (799122120001), we get a palindrome (899143341998).

The spelling of 100021221997 in words is "one hundred billion, twenty-one million, two hundred twenty-one thousand, nine hundred ninety-seven".