21655355320 has 16 divisors (see below), whose sum is σ = 48724549560. Its totient is φ = 8662142112.

The previous prime is 21655355303. The next prime is 21655355341. The reversal of 21655355320 is 2355355612.

It is a self number, because there is not a number n which added to its sum of digits gives 21655355320.

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, 270691902 + ... + 270691981.

Almost surely, 2^21655355320 is an apocalyptic number.

21655355320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21655355320 is an abundant number, since it is smaller than the sum of its proper divisors (27069194240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21655355320 is a wasteful number, since it uses less digits than its factorization.

21655355320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541383894 (or 541383890 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 37.

The spelling of 21655355320 in words is "twenty-one billion, six hundred fifty-five million, three hundred fifty-five thousand, three hundred twenty".