21515423052020 has 24 divisors (see below), whose sum is σ = 46034886306024. Its totient is φ = 8443788669056.

The previous prime is 21515423052017. The next prime is 21515423052029. The reversal of 21515423052020 is 2025032451512.

It can be written as a sum of positive squares in 4 ways, for example, as 3982594974736 + 17532828077284 = 1995644^2 + 4187222^2 .

It is a super-2 number, since 2×21515423052020² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21515423052029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10148783399 + ... + 10148785518.

It is an arithmetic number, because the mean of its divisors is an integer number (1918120262751).

Almost surely, 2^{21515423052020} is an apocalyptic number.

21515423052020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21515423052020 is an abundant number, since it is smaller than the sum of its proper divisors (24519463254004).

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

21515423052020 is a wasteful number, since it uses less digits than its factorization.

21515423052020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20297568979 (or 20297568977 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 32.

The spelling of 21515423052020 in words is "twenty-one trillion, five hundred fifteen billion, four hundred twenty-three million, fifty-two thousand, twenty".