21166210552 has 16 divisors (see below), whose sum is σ = 41412151440. Its totient is φ = 10122970176.

The previous prime is 21166210547. The next prime is 21166210561. The reversal of 21166210552 is 25501266112.

It is a super-2 number, since 2×21166210552² (a number of 21 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 3 ways as a sum of consecutive naturals, for example, 57516693 + ... + 57517060.

It is an arithmetic number, because the mean of its divisors is an integer number (2588259465).

Almost surely, 2^21166210552 is an apocalyptic number.

It is an amenable number.

21166210552 is a deficient number, since it is larger than the sum of its proper divisors (20245940888).

21166210552 is a wasteful number, since it uses less digits than its factorization.

21166210552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115033782 (or 115033778 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 21166210552 its reverse (25501266112), we get a palindrome (46667476664).

The spelling of 21166210552 in words is "twenty-one billion, one hundred sixty-six million, two hundred ten thousand, five hundred fifty-two".