21152212054566 has 16 divisors (see below), whose sum is σ = 42357503697264. Its totient is φ = 7041890753504.

The previous prime is 21152212054537. The next prime is 21152212054573. The reversal of 21152212054566 is 66545021225112.

It is a super-2 number, since 2×21152212054566² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2211644325 + ... + 2211653888.

It is an arithmetic number, because the mean of its divisors is an integer number (2647343981079).

Almost surely, 2^{21152212054566} is an apocalyptic number.

21152212054566 is an abundant number, since it is smaller than the sum of its proper divisors (21205291642698).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21152212054566 is a wasteful number, since it uses less digits than its factorization.

21152212054566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4423299015.

The product of its (nonzero) digits is 288000, while the sum is 42.

Adding to 21152212054566 its reverse (66545021225112), we get a palindrome (87697233279678).

The spelling of 21152212054566 in words is "twenty-one trillion, one hundred fifty-two billion, two hundred twelve million, fifty-four thousand, five hundred sixty-six".