21961604515041 has 9 divisors (see below), whose sum is σ = 31722337940241. Its totient is φ = 14641060304052.

The previous prime is 21961604515031. The next prime is 21961604515069. The reversal of 21961604515041 is 14051540616912.

The square root of 21961604515041 is 4686321.

It is a perfect power (a square), and thus also a powerful number.

21961604515041 is a `hidden beast` number, since 2 + 1 + 96 + 1 + 6 + 0 + 4 + 51 + 504 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21961604515041 - 2⁵ = 21961604515009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21961604515031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13277910 + ... + 14840016.

Almost surely, 2^{21961604515041} is an apocalyptic number.

21961604515041 is the 4686321-st square number.

21961604515041 is the 2343161-st centered octagonal number.

It is an amenable number.

21961604515041 is a deficient number, since it is larger than the sum of its proper divisors (9760733425200).

21961604515041 is an frugal number, since it uses more digits than its factorization.

21961604515041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3124220 (or 1562110 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 21961604515041 in words is "twenty-one trillion, nine hundred sixty-one billion, six hundred four million, five hundred fifteen thousand, forty-one".