10197806921 has 2 divisors, whose sum is σ = 10197806922. Its totient is φ = 10197806920.

The previous prime is 10197806917. The next prime is 10197806933. The reversal of 10197806921 is 12960879101.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8534064400 + 1663742521 = 92380^2 + 40789^2 .

It is a cyclic number.

It is not a de Polignac number, because 10197806921 - 2² = 10197806917 is a prime.

It is not a weakly prime, because it can be changed into another prime (10197803921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5098903460 + 5098903461.

It is an arithmetic number, because the mean of its divisors is an integer number (5098903461).

Almost surely, 2^10197806921 is an apocalyptic number.

It is an amenable number.

10197806921 is a deficient number, since it is larger than the sum of its proper divisors (1).

10197806921 is an equidigital number, since it uses as much as digits as its factorization.

10197806921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 44.

The spelling of 10197806921 in words is "ten billion, one hundred ninety-seven million, eight hundred six thousand, nine hundred twenty-one".