21152515262566 has 8 divisors (see below), whose sum is σ = 32130402930720. Its totient is φ = 10442380952328.

The previous prime is 21152515262503. The next prime is 21152515262569. The reversal of 21152515262566 is 66526251525112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152515262569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66938339281 + ... + 66938339596.

It is an arithmetic number, because the mean of its divisors is an integer number (4016300366340).

Almost surely, 2^{21152515262566} is an apocalyptic number.

21152515262566 is a deficient number, since it is larger than the sum of its proper divisors (10977887668154).

21152515262566 is a wasteful number, since it uses less digits than its factorization.

21152515262566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133876678958.

The product of its digits is 2160000, while the sum is 49.

Adding to 21152515262566 its reverse (66526251525112), we get a palindrome (87678766787678).

The spelling of 21152515262566 in words is "twenty-one trillion, one hundred fifty-two billion, five hundred fifteen million, two hundred sixty-two thousand, five hundred sixty-six".