21071153664 has 240 divisors, whose sum is σ = 66804813504. Its totient is φ = 6340608000.

The previous prime is 21071153651. The next prime is 21071153671. The reversal of 21071153664 is 46635117012.

21071153664 is a `hidden beast` number, since 2 + 107 + 11 + 536 + 6 + 4 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7652512 + ... + 7655264.

Almost surely, 2^21071153664 is an apocalyptic number.

21071153664 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 21071153664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33402406752).

21071153664 is an abundant number, since it is smaller than the sum of its proper divisors (45733659840).

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

21071153664 is a wasteful number, since it uses less digits than its factorization.

21071153664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2939 (or 2920 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The spelling of 21071153664 in words is "twenty-one billion, seventy-one million, one hundred fifty-three thousand, six hundred sixty-four".