21365129617608 has 256 divisors, whose sum is σ = 62132394240000. Its totient is φ = 5996415744000.

The previous prime is 21365129617541. The next prime is 21365129617609. The reversal of 21365129617608 is 80671692156312.

It is not an unprimeable number, because it can be changed into a prime (21365129617609) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7007256468 + ... + 7007259516.

It is an arithmetic number, because the mean of its divisors is an integer number (242704665000).

Almost surely, 2^{21365129617608} is an apocalyptic number.

21365129617608 is a gapful number since it is divisible by the number (28) 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 21365129617608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31066197120000).

21365129617608 is an abundant number, since it is smaller than the sum of its proper divisors (40767264622392).

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

21365129617608 is a wasteful number, since it uses less digits than its factorization.

21365129617608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6276 (or 6272 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 57.

The spelling of 21365129617608 in words is "twenty-one trillion, three hundred sixty-five billion, one hundred twenty-nine million, six hundred seventeen thousand, six hundred eight".