21001926032640 has 2160 divisors, whose sum is σ = 90274320525312. Its totient is φ = 4645737234432.

The previous prime is 21001926032623. The next prime is 21001926032651. The reversal of 21001926032640 is 4623062910012.

It is a happy number.

21001926032640 is a `hidden beast` number, since 2 + 1 + 0 + 0 + 1 + 9 + 2 + 6 + 0 + 3 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (2160).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21001926032595 and 21001926032604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 27743627142 + ... + 27743627898.

Almost surely, 2^{21001926032640} is an apocalyptic number.

21001926032640 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 21001926032640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45137160262656).

21001926032640 is an abundant number, since it is smaller than the sum of its proper divisors (69272394492672).

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

21001926032640 is a wasteful number, since it uses less digits than its factorization.

21001926032640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 974 (or 944 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

Adding to 21001926032640 its reverse (4623062910012), we get a palindrome (25624988942652).

The spelling of 21001926032640 in words is "twenty-one trillion, one billion, nine hundred twenty-six million, thirty-two thousand, six hundred forty".