21015155052020 has 24 divisors (see below), whose sum is σ = 44162198571624. Its totient is φ = 8400276694656.

The previous prime is 21015155051987. The next prime is 21015155052037. The reversal of 21015155052020 is 2025055151012.

It can be written as a sum of positive squares in 4 ways, for example, as 12641921580304 + 8373233471716 = 3555548^2 + 2893654^2 .

It is a congruent number.

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, 361553099 + ... + 361611218.

It is an arithmetic number, because the mean of its divisors is an integer number (1840091607151).

Almost surely, 2^{21015155052020} is an apocalyptic number.

21015155052020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21015155052020 is an abundant number, since it is smaller than the sum of its proper divisors (23147043519604).

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

21015155052020 is a wasteful number, since it uses less digits than its factorization.

21015155052020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723165779 (or 723165777 counting only the distinct ones).

The product of its (nonzero) digits is 5000, while the sum is 29.

The spelling of 21015155052020 in words is "twenty-one trillion, fifteen billion, one hundred fifty-five million, fifty-two thousand, twenty".