21155534620 has 48 divisors (see below), whose sum is σ = 48935996928. Its totient is φ = 7618224960.

The previous prime is 21155534593. The next prime is 21155534627. The reversal of 21155534620 is 2643555112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155534627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 444144 + ... + 489463.

It is an arithmetic number, because the mean of its divisors is an integer number (1019499936).

Almost surely, 2^21155534620 is an apocalyptic number.

21155534620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155534620 is an abundant number, since it is smaller than the sum of its proper divisors (27780462308).

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

21155534620 is a wasteful number, since it uses less digits than its factorization.

21155534620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 933730 (or 933728 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 34.

The spelling of 21155534620 in words is "twenty-one billion, one hundred fifty-five million, five hundred thirty-four thousand, six hundred twenty".