21222765655 has 24 divisors (see below), whose sum is σ = 31516623072. Its totient is φ = 13433307264.

The previous prime is 21222765647. The next prime is 21222765691. The reversal of 21222765655 is 55656722212.

It is not a de Polignac number, because 21222765655 - 2³ = 21222765647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1788064 + ... + 1799893.

It is an arithmetic number, because the mean of its divisors is an integer number (1313192628).

Almost surely, 2^21222765655 is an apocalyptic number.

21222765655 is a deficient number, since it is larger than the sum of its proper divisors (10293857417).

21222765655 is a wasteful number, since it uses less digits than its factorization.

21222765655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3587995 (or 3587982 counting only the distinct ones).

The product of its digits is 504000, while the sum is 43.

The spelling of 21222765655 in words is "twenty-one billion, two hundred twenty-two million, seven hundred sixty-five thousand, six hundred fifty-five".