21515420155040 has 192 divisors, whose sum is σ = 59613536666880. Its totient is φ = 7185460838400.

The previous prime is 21515420155003. The next prime is 21515420155069. The reversal of 21515420155040 is 4055102451512.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 6947240 + ... + 9554840.

It is an arithmetic number, because the mean of its divisors is an integer number (310487170140).

Almost surely, 2^{21515420155040} is an apocalyptic number.

21515420155040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21515420155040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29806768333440).

21515420155040 is an abundant number, since it is smaller than the sum of its proper divisors (38098116511840).

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

21515420155040 is a wasteful number, since it uses less digits than its factorization.

21515420155040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2607815 (or 2607807 counting only the distinct ones).

The product of its (nonzero) digits is 40000, while the sum is 35.

The spelling of 21515420155040 in words is "twenty-one trillion, five hundred fifteen billion, four hundred twenty million, one hundred fifty-five thousand, forty".