21655211645 has 8 divisors (see below), whose sum is σ = 26000183904. Its totient is φ = 17314882704.

The previous prime is 21655211587. The next prime is 21655211657. The reversal of 21655211645 is 54611255612.

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

It is a cyclic number.

It is not a de Polignac number, because 21655211645 - 2⁶ = 21655211581 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21655211599 and 21655211608.

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, 1150559 + ... + 1169228.

It is an arithmetic number, because the mean of its divisors is an integer number (3250022988).

Almost surely, 2^21655211645 is an apocalyptic number.

It is an amenable number.

21655211645 is a deficient number, since it is larger than the sum of its proper divisors (4344972259).

21655211645 is a wasteful number, since it uses less digits than its factorization.

21655211645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2321659.

The product of its digits is 72000, while the sum is 38.

The spelling of 21655211645 in words is "twenty-one billion, six hundred fifty-five million, two hundred eleven thousand, six hundred forty-five".