20101210209961 has 2 divisors, whose sum is σ = 20101210209962. Its totient is φ = 20101210209960.

The previous prime is 20101210209931. The next prime is 20101210210049. The reversal of 20101210209961 is 16990201210102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19018486718361 + 1082723491600 = 4361019^2 + 1040540^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101210209961 - 2⁷ = 20101210209833 is a prime.

It is not a weakly prime, because it can be changed into another prime (20101210209911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050605104980 + 10050605104981.

It is an arithmetic number, because the mean of its divisors is an integer number (10050605104981).

Almost surely, 2^{20101210209961} is an apocalyptic number.

It is an amenable number.

20101210209961 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101210209961 is an equidigital number, since it uses as much as digits as its factorization.

20101210209961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 34.

The spelling of 20101210209961 in words is "twenty trillion, one hundred one billion, two hundred ten million, two hundred nine thousand, nine hundred sixty-one".