21201057961 has 2 divisors, whose sum is σ = 21201057962. Its totient is φ = 21201057960.

The previous prime is 21201057919. The next prime is 21201058001. The reversal of 21201057961 is 16975010212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19916265625 + 1284792336 = 141125^2 + 35844^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201057961 - 2¹¹ = 21201055913 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201057061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600528980 + 10600528981.

It is an arithmetic number, because the mean of its divisors is an integer number (10600528981).

Almost surely, 2^21201057961 is an apocalyptic number.

It is an amenable number.

21201057961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201057961 is an equidigital number, since it uses as much as digits as its factorization.

21201057961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7560, while the sum is 34.

The spelling of 21201057961 in words is "twenty-one billion, two hundred one million, fifty-seven thousand, nine hundred sixty-one".