21297421790064 has 320 divisors, whose sum is σ = 70863130183680. Its totient is φ = 5998040616960.

The previous prime is 21297421790059. The next prime is 21297421790083. The reversal of 21297421790064 is 46009712479212.

21297421790064 is a `hidden beast` number, since 2 + 1 + 2 + 97 + 421 + 79 + 0 + 0 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1721275782 + ... + 1721288154.

It is an arithmetic number, because the mean of its divisors is an integer number (221447281824).

Almost surely, 2^{21297421790064} is an apocalyptic number.

21297421790064 is a gapful number since it is divisible by the number (24) 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 21297421790064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35431565091840).

21297421790064 is an abundant number, since it is smaller than the sum of its proper divisors (49565708393616).

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

21297421790064 is a wasteful number, since it uses less digits than its factorization.

21297421790064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20485 (or 20473 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 21297421790064 in words is "twenty-one trillion, two hundred ninety-seven billion, four hundred twenty-one million, seven hundred ninety thousand, sixty-four".