21512029040640 has 832 divisors, whose sum is σ = 78190483937280. Its totient is φ = 5679628222464.

The previous prime is 21512029040629. The next prime is 21512029040647. The reversal of 21512029040640 is 4604092021512.

It is a happy number.

21512029040640 is a `hidden beast` number, since 2 + 1 + 5 + 1 + 2 + 0 + 2 + 9 + 0 + 4 + 0 + 640 = 666.

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 = 21512029040595 and 21512029040604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512029040647) 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, 4613342949 + ... + 4613347611.

It is an arithmetic number, because the mean of its divisors is an integer number (93978947040).

Almost surely, 2^{21512029040640} is an apocalyptic number.

21512029040640 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 21512029040640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39095241968640).

21512029040640 is an abundant number, since it is smaller than the sum of its proper divisors (56678454896640).

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

21512029040640 is an frugal number, since it uses more digits than its factorization.

21512029040640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4816 (or 4776 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 21512029040640 in words is "twenty-one trillion, five hundred twelve billion, twenty-nine million, forty thousand, six hundred forty".