21141508961 has 2 divisors, whose sum is σ = 21141508962. Its totient is φ = 21141508960.

The previous prime is 21141508951. The next prime is 21141508963. The reversal of 21141508961 is 16980514112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21090300625 + 51208336 = 145225^2 + 7156^2 .

It is a cyclic number.

It is not a de Polignac number, because 21141508961 - 2³⁴ = 3961639777 is a prime.

It is a super-2 number, since 2×21141508961² (a number of 21 digits) contains 22 as substring.

Together with 21141508963, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21141508963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570754480 + 10570754481.

It is an arithmetic number, because the mean of its divisors is an integer number (10570754481).

Almost surely, 2^21141508961 is an apocalyptic number.

It is an amenable number.

21141508961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21141508961 is an equidigital number, since it uses as much as digits as its factorization.

21141508961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 38.

The spelling of 21141508961 in words is "twenty-one billion, one hundred forty-one million, five hundred eight thousand, nine hundred sixty-one".