21155002513420 has 24 divisors (see below), whose sum is σ = 44425636945200. Its totient is φ = 8461975925952.

The previous prime is 21155002513373. The next prime is 21155002513441. The reversal of 21155002513420 is 2431520055112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6316611 + ... + 9066949.

It is an arithmetic number, because the mean of its divisors is an integer number (1851068206050).

Almost surely, 2^{21155002513420} is an apocalyptic number.

21155002513420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21155002513420 is an abundant number, since it is smaller than the sum of its proper divisors (23270634431780).

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

21155002513420 is a wasteful number, since it uses less digits than its factorization.

21155002513420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3134937 (or 3134935 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 21155002513420 its reverse (2431520055112), we get a palindrome (23586522568532).

The spelling of 21155002513420 in words is "twenty-one trillion, one hundred fifty-five billion, two million, five hundred thirteen thousand, four hundred twenty".