21655175656 has 16 divisors (see below), whose sum is σ = 41593783140. Its totient is φ = 10563500160.

The previous prime is 21655175651. The next prime is 21655175657. The reversal of 21655175656 is 65657155612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14600855556 + 7054320100 = 120834^2 + 83990^2 .

It is not an unprimeable number, because it can be changed into a prime (21655175651) 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, 33010611 + ... + 33011266.

Almost surely, 2^21655175656 is an apocalyptic number.

It is an amenable number.

21655175656 is a deficient number, since it is larger than the sum of its proper divisors (19938607484).

21655175656 is a wasteful number, since it uses less digits than its factorization.

21655175656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66021924 (or 66021920 counting only the distinct ones).

The product of its digits is 1890000, while the sum is 49.

The spelling of 21655175656 in words is "twenty-one billion, six hundred fifty-five million, one hundred seventy-five thousand, six hundred fifty-six".