21566203102 has 4 divisors (see below), whose sum is σ = 32349304656. Its totient is φ = 10783101550.

The previous prime is 21566203081. The next prime is 21566203151. The reversal of 21566203102 is 20130266512.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21566203102² (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 as a sum of consecutive naturals, namely, 5391550774 + ... + 5391550777.

It is an arithmetic number, because the mean of its divisors is an integer number (8087326164).

Almost surely, 2^21566203102 is an apocalyptic number.

21566203102 is a deficient number, since it is larger than the sum of its proper divisors (10783101554).

21566203102 is a wasteful number, since it uses less digits than its factorization.

21566203102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10783101553.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 21566203102 its reverse (20130266512), we get a palindrome (41696469614).

The spelling of 21566203102 in words is "twenty-one billion, five hundred sixty-six million, two hundred three thousand, one hundred two".