21155335040 has 64 divisors (see below), whose sum is σ = 57799409760. Its totient is φ = 7253256192.

The previous prime is 21155335037. The next prime is 21155335043. The reversal of 21155335040 is 4053355112.

It is an interprime number because it is at equal distance from previous prime (21155335037) and next prime (21155335043).

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 21155334994 and 21155335012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155335043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2356607 + ... + 2365566.

Almost surely, 2^21155335040 is an apocalyptic number.

21155335040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155335040 is an abundant number, since it is smaller than the sum of its proper divisors (36644074720).

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

21155335040 is an equidigital number, since it uses as much as digits as its factorization.

21155335040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4722199 (or 4722187 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 21155335040 in words is "twenty-one billion, one hundred fifty-five million, three hundred thirty-five thousand, forty".