994721136639961 has 2 divisors, whose sum is σ = 994721136639962. Its totient is φ = 994721136639960.

The previous prime is 994721136639953. The next prime is 994721136640019. The reversal of 994721136639961 is 169936631127499.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 819125006529600 + 175596130110361 = 28620360^2 + 13251269^2 .

It is an emirp because it is prime and its reverse (169936631127499) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 994721136639961 - 2³ = 994721136639953 is a prime.

It is not a weakly prime, because it can be changed into another prime (994721136639361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497360568319980 + 497360568319981.

It is an arithmetic number, because the mean of its divisors is an integer number (497360568319981).

Almost surely, 2^{994721136639961} is an apocalyptic number.

It is an amenable number.

994721136639961 is a deficient number, since it is larger than the sum of its proper divisors (1).

994721136639961 is an equidigital number, since it uses as much as digits as its factorization.

994721136639961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 714256704, while the sum is 76.

The spelling of 994721136639961 in words is "nine hundred ninety-four trillion, seven hundred twenty-one billion, one hundred thirty-six million, six hundred thirty-nine thousand, nine hundred sixty-one".