21555520340 has 48 divisors (see below), whose sum is σ = 45507559104. Its totient is φ = 8576409600.

The previous prime is 21555520319. The next prime is 21555520361. The reversal of 21555520340 is 4302555512.

It is an interprime number because it is at equal distance from previous prime (21555520319) and next prime (21555520361).

It is a junction number, because it is equal to n+sod(n) for n = 21555520297 and 21555520306.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4165955 + ... + 4171125.

It is an arithmetic number, because the mean of its divisors is an integer number (948074148).

Almost surely, 2^21555520340 is an apocalyptic number.

21555520340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21555520340 is an abundant number, since it is smaller than the sum of its proper divisors (23952038764).

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

21555520340 is a wasteful number, since it uses less digits than its factorization.

21555520340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6248 (or 6246 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 32.

The spelling of 21555520340 in words is "twenty-one billion, five hundred fifty-five million, five hundred twenty thousand, three hundred forty".