21555543040 has 88 divisors (see below), whose sum is σ = 54749913552. Its totient is φ = 8114995200.

The previous prime is 21555543001. The next prime is 21555543047. The reversal of 21555543040 is 4034555512.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 21555542987 and 21555543005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555543047) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36786 + ... + 210865.

Almost surely, 2^21555543040 is an apocalyptic number.

21555543040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21555543040 is an abundant number, since it is smaller than the sum of its proper divisors (33194370512).

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

21555543040 is a wasteful number, since it uses less digits than its factorization.

21555543040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247693 (or 247675 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 34.

The spelling of 21555543040 in words is "twenty-one billion, five hundred fifty-five million, five hundred forty-three thousand, forty".